Researchers found a malicious AGENTS markdown instruction file in a customer’s Downloads folder that tricked an AI coding agent into installing a rogue npm package. They reproduced the attack against OpenAI Codex and demonstrated a related technique against Claude Code to leak OAuth tokens and hijack the account using only the malicious instructions. Markdown files such as AGENTS.md are plain-text files that contain project-specific instructions for AI coding agents, such as the tools to use, how to run tests, and the coding conventions to follow. Researchers at Forever Security, a company that monitors for risks introduced by AI agents and autonomous software, discovered the tactic on a customer’s computer, where a coding agent attempted to install the malicious npm package ‘function-color.’
Pierluigi Paganini answers questions about the PHP2Shell vulnerability, early exploitation, AI-assisted attacks, and the risks to businesses, servers, and personal data. 1. Your latest report reveals that hackers began exploiting the PHP2Shell vulnerability four days before it was publicly disclosed. First, can you explain what PHP is, how widely it is used across the internet, and why this particular security flaw is so serious? PHP is a programming language widely used to build websites and web applications. It powers a significant share of the web. PHP2Shell is serious because it can allow attackers to execute commands on a vulnerable server remotely. Depending on the configuration and the server’s privileges, this could give threat actors access to sensitive data, applications and other systems. 2. According to AWS researchers, attacks were already underway before the vulnerability became public. How did researchers uncover this early exploitation, and what does it tell us about the ability of hackers to identify security weaknesses before developers can fix them? AWS researchers detected exploitation attempts against their honeypot network four days before public disclosure and the release of patches. This shows that attackers can discover or weaponize vulnerabilities before defenders have time to respond. AI-assisted analysis may accelerate this process, helping attackers turn technical information into working exploits in hours rather than days. However, detected attempts do not automatically mean successful compromises. 3. The vulnerability could potentially allow attackers to execute malicious commands on affected servers. What does that mean in practical terms, and what risks does it pose to websites, businesses and the personal information of their users? Remote command execution means an attacker may be able to make a server run commands without authorization. Depending on the attacker’s access, they could steal data, install malware, change website content, or use the compromised server to attack other systems. Businesses could face service disruption, financial losses and reputational damage. Users may also be exposed if their personal information is stored on an affected system. The actual impact depends on the server’s configuration and security controls. 4. The latest findings raise concerns about the gap between discovering a vulnerability and protecting systems against it. How quickly can attackers exploit these weaknesses, and are businesses adequately prepared to respond when critical security flaws emerge? The window can be extremely short. In some cases, attackers can develop or adapt an exploit within hours, leaving organizations little time to react. Many businesses still rely on patching schedules that are too slow for internet-facing systems. Organizations need continuous monitoring, rapid patching, tested incident response plans and clear visibility into exposed assets. They should also investigate suspicious activity dating back to before a vulnerability was publicly disclosed, because attacks may already be underway. 5. With PHP powering a significant portion of the internet, could we see further attacks exploiting this vulnerability? What should website operators do immediately to protect their systems, and should ordinary internet users be concerned about their data? Further attacks are possible, particularly against systems that remain unpatched or exposed. Website operators should apply the relevant security updates, check whether their PHP applications are vulnerable, and review logs for suspicious activity dating back to October 17. They should also restrict access and investigate signs of compromise. Ordinary users do not need to panic, but they should keep their accounts protected with unique passwords and multi-factor authentication where available. Whether personal data is at risk depends on which services they use and whether those systems were compromised. AI-assisted tools are increasingly being used to analyze code and identify vulnerabilities. How much of a role could artificial intelligence play in helping attackers discover and exploit flaws like PHP2Shell, and can defenders use the same technology to their advantage? AI can help analyze code, identify suspicious patterns and speed up the process of turning a vulnerability into a working exploit. This lowers some of the technical barriers for attackers and may shorten the time between discovering a flaw and exploiting it. However, AI is not the only factor, and we should not assume that every attack is AI-driven. Defenders can use the same capabilities to review code, prioritize vulnerabilities, analyze logs and detect suspicious behavior. The real advantage comes from combining AI with reliable data, skilled security teams and effective response processes. This case shows that attackers may exploit a vulnerability before a patch is available. Does this mean traditional vulnerability management is no longer enough, and how should organizations rethink their security strategy? Traditional vulnerability management remains essential, but patching alone is not enough when attackers may act before a fix becomes available. Organizations need to know which internet-facing systems they operate, understand their exposure and have additional controls in place. These include limiting access to vulnerable services, monitoring suspicious activity, applying temporary mitigations and preparing incident response procedures. They should also investigate whether systems were targeted before the vulnerability was disclosed. The goal is to reduce the opportunity for exploitation and detect attacks quickly, even when a patch is not yet available. Below is another interview I gave to TRT World discussing critical PHP vulnerabilities, the risks they pose to web servers, and the growing number of exploitation attempts. I explain why rapid patching and effective security measures are essential to minimize potential damage. Follow me on Twitter: @securityaffairs and Facebook and Mastodon Pierluigi Paganini (SecurityAffairs – hacking, newsletter)
U.S. Cybersecurity and Infrastructure Security Agency (CISA) adds Collabora Online flaw to its Known Exploited Vulnerabilities catalog. The U.S. Cybersecurity and Infrastructure Security Agency (CISA) added a Collabora Collabora Online – Built-in CODE Server flaw, tracked as CVE-2026-110447 (CVSS score of 9.2), to its Known Exploited Vulnerabilities (KEV) catalog. Collabora Online – Built-in CODE Server is an app for Nextcloud that lets you open, edit and collaborate on documents, spreadsheets and presentations directly in your browser, without needing Microsoft Office installed on your computer. It is based on Collabora Online and LibreOffice technology. CVE-2026-110447 is a critical OS command injection flaw in Nextcloud’s proxy.php that affects Collabora Online Built-in CODE Server before 26.4.303. Unauthenticated attackers can execute commands when the built-in server is stopped. Standalone Collabora servers are not affected. Update immediately. In versions up to 26.4.302, proxy.php included request data in a Bash command without proper sanitization, allowing attackers to execute OS commands as the web server user. Exploitation is possible only when the local CODE server is stopped, such as during a restart, upgrade or crash. The script runs directly through the web server without loading Nextcloud’s code. Exploitation has been reported since September 2026, with attackers deploying PHP web shells and stealing configuration files containing credentials and application secrets. Three administrators reported the vulnerability on GitHub, while the first recorded attack dates back to September 10. The first attack was reported by a Nextcloud administrator whose servers had been compromised. Logs showed malicious requests on September 10 and 11, 2026, from the same IP, targeting proxy.php on version 26.4.302. The attackers deployed a PHP web shell and searched one server for credential stores and cryptocurrency wallets. Although reviewed logs showed no file exfiltration commands, data accessible to the web server account must be considered potentially exposed. Two other administrators reported similar incidents, but none found evidence of root access. After updating to 26.4.303, one administrator recorded another attempt on September 14, but no new shell appeared. Project maintainer mmeeks urged users to update and remove leftover shx*.php files. The CVE record confirms exploitation in September and October 2026, but the total number of compromised servers remains unknown. The flaw affects only the Development Edition’s Built-in CODE Server deployment. According to Binding Operational Directive (BOD) 22-01: Reducing the Significant Risk of Known Exploited Vulnerabilities, FCEB agencies have to address the identified vulnerabilities by the due date to protect their networks against attacks exploiting the flaws in the catalog. Experts also recommend that private organizations review the Catalog and address the vulnerabilities in their infrastructure. CISA orders federal agencies to fix the flaw by October 26, 2026. Follow me on Twitter: @securityaffairs and Facebook and Mastodon Pierluigi Paganini (SecurityAffairs – hacking, CISA)
Capcom disclosed a data breach exposing 11.7 million email addresses and account details after hackers accessed its CAPCOM ID service. Japanese gaming company Capcom has disclosed a data breach discovered on October 19 involving its CAPCOM ID service, which provides access to online services and games. As of October 22, attackers stole 11,774,247 email addresses, along with account details including creation dates, last login dates, login counts, and the IP addresses used for the latest logins. “We have recently discovered that unauthorized access by a third party occurred to our online membership service “CAPCOM ID” (*1) , resulting in the leakage of some customer information.” reads the company’s notice. “Number of leaked email addresses and system-specific identification information: 11,774,247 (worldwide total)” In 43 cases, hackers exposed date of birth, gender, country/region, and nickname. Capcom also reported that attackers illegally changed passwords on 196 accounts, and the company has already reset them. The company said the incident exposed personal information belonging to a small number of individuals. Capcom has activated its incident response procedures and confirmed that services using CAPCOM ID remain operational. The company has notified the relevant authorities, is investigating the breach, and has begun contacting affected customers through a dedicated support channel. The company also urges users to watch out for phishing attempts involving emails impersonating Capcom or its partners, particularly those containing suspicious links or attachments. It says it will investigate the incident, address the identified causes, and strengthen its security measures to prevent similar breaches. “In response, we implemented emergency measures and began identifying and addressing the attack method.” states the notice.”A task force was established within the company to gather information and take measures to prevent further damage. The investigation revealed that some customer information registered with “CAPCOM ID” had been leaked. In addition, unauthorized password changes were confirmed for some accounts. On the same day, the incident was reported to the Security Oversight Committee, our external advisory organization.” Capcom was previously targeted by the Ragnar Locker ransomware gang in November 2020. The attackers claimed to have stolen 1 TB of data, potentially affecting up to 390,000 people. Follow me on Twitter: @securityaffairs and Facebook and Mastodon Pierluigi Paganini (SecurityAffairs – hacking, data breach)
U.S. Cybersecurity and Infrastructure Security Agency (CISA) adds Arista VeloCloud Orchestrator flaw to its Known Exploited Vulnerabilities catalog. The U.S. Cybersecurity and Infrastructure Security Agency (CISA) added a critical Arista VeloCloud Orchestrator flaw, tracked as CVE-2026-114625 (CVSS score of 9.4), to its Known Exploited Vulnerabilities (KEV) catalog. VeloCloud Orchestrator (VCO) is the central management system for VMware SD-WAN, a technology that helps companies securely connect offices, data centers, cloud services, and remote sites over wide-area networks. It is now associated with Arista Networks, which acquired VMware’s SD-WAN business. The orchestrator gives network administrators a central place to configure, monitor, and manage the network. The flaw is a SQL Injection issue that affects on-premises VeloCloud Orchestrator (VCO). It allows an authenticated user to gain operator privileges and impersonate a local superuser operator account. This could give a remote attacker access to internal functions that should not be remotely available, potentially compromising the system and the data it manages. Hosted VCO versions, including Dedicated, were also affected but have already been patched. “VeloCloud Orchestrator (VCO) on-prem has a security issue where this issue may allow a remote attacker to access privileged internal functionality and impact the VCO host. Successful exploitation may compromise the confidentiality, integrity, and availability of the orchestrator and data managed by the orchestrator.” reads the advisory. “On an affected system, any authenticated user can gain operator privileges and masquerade as a local “superuser operator” user. This includes access to functionality that is intended for internal use only and which is not intended to be remotely accessible.” VeloCloud Orchestrator (VCO) is vulnerable by default. An attacker needs access to its web interface and a valid account. Even an account with the lowest permission level, Enterprise Read Only, is enough. No configuration change can prevent this exposure. Administrators should check web access logs for unusual requests, encoded text, attempts to access internal services, or an unusually high number of requests. They should also block these IP addresses linked to attacks: 74.82.197.86 38.54.50.151 If an attack is suspected, administrators should save web, application, system and database logs, along with relevant file timestamps, before starting recovery, if possible. According to Binding Operational Directive (BOD) 22-01: Reducing the Significant Risk of Known Exploited Vulnerabilities, FCEB agencies have to address the identified vulnerabilities by the due date to protect their networks against attacks exploiting the flaws in the catalog. Experts also recommend that private organizations review the Catalog and address the vulnerabilities in their infrastructure. CISA orders federal agencies to fix the flaw by October 26, 2026. Follow me on Twitter: @securityaffairs and Facebook and Mastodon Pierluigi Paganini (SecurityAffairs – hacking, CISA)
PHP warns of a new, unlikely code execution flaw, CVE-2026-115560, and advises disabling session upload progress until a fix is released. PHP has warned of a new code execution vulnerability, tracked as CVE-2026-115560, just two days after releasing emergency patches for the critical PHP2Shell flaws. The vulnerability affects only a specific PHP configuration that PHP says is unlikely to be used in practice. An application must meet several conditions: it must configure session.serialize_handler as php_binary or php_serialize, change it to php at runtime using ini_set(), and make this change before calling session_start(). Session upload progress must also remain enabled. In an advisory published on October 23, the project recommended disabling session upload progress until a fix becomes available in a regular release. The vulnerability is separate from PHP2Shell and is not fixed by the October 21 updates for PHP versions 8.2.35, 8.3.36, 8.4.27 and 8.5.12. “The issue can only occur under an unusual combination of configuration and application code. An application must set session.serialize_handler to php_binary or php_serialize in its configuration and then switch it to php at runtime with ini_set() before calling session_start(). Session upload progress must also still be enabled.” reads the advisory. “Applications that never change the serialize handler at runtime can keep the feature enabled. Since this setup is unlikely in practice, we are handling it in the regular release cycle and will publish a full advisory for CVE-2026-115560 with the next release.” Applications that do not change the serialization handler while running are not exposed through this attack path, even if session upload progress is enabled. PHP recommends a simple temporary fix: set session.upload_progress.enabled=0 until the next routine bugfix release. This is the same mitigation already recommended in the October 21 advisory for CVE-2026-109619. Administrators who applied this setting and have kept it in place do not need to take further action for this issue. Session upload progress is enabled by default and allows applications to track the progress of file uploads. Disabling it reduces exposure to this specific vulnerability path. PHP will fix CVE-2026-115560 through its regular release cycle because the vulnerable setup is uncommon. It plans to publish a full advisory with the next release. PHP has not yet identified affected versions, confirmed when the fix will arrive, assigned a severity score, or explained whether the flaw shares a root cause with CVE-2026-109619. No attacks targeting this new issue have been reported. On October 21, PHP released emergency patches for two critical vulnerabilities tracked as CVE-2026-109618 and CVE-2026-109619 (CVSS score of 9.2), affecting every PHP version that handles web requests. The bug code dates back to PHP 5.4 from 2012, lives in the PHP engine itself rather than in any application, and allows unauthenticated remote code execution via crafted HTTP requests. Cloudflare researchers observed tens of thousands of exploit attempts within 45 minutes of public disclosure, hundreds of thousands within two hours, and millions by October 22. Follow me on Twitter: @securityaffairs and Facebook and Mastodon Pierluigi Paganini (SecurityAffairs – hacking, PHP)
Cybersecurity researchers have discovered an artificial intelligence (AI)-driven intrusion ecosystem run by affiliates of the INC and The Gentlemen ransomware groups. Central to the operation is an "Autonomous Red Team Kill Chain Framework" referred to as Phantom. The threat actor is assessed to be Russian-speaking and functions both as an intrusion and data-extortion operator, as well as an
The PHP security team has shared mitigation measures for a new remote code execution vulnerability that affects systems with non-default configurations and has no patch. PHP is an open-source web development language used by nearly 70% of all websites on the Internet. According to VirusTotal estimates, more than 5.1 million PHP hosts are exposed online, and roughly 3.8 million have at least one port open to attacks. According to a Friday advisory, this security flaw (tracked as CVE-2026-115560) can only be exploited when targeting systems "with an unusual combination of configuration and application code." "An application must set session.serialize_handler to php_binary or php_serialize in its configuration and then switch it to php at runtime with ini_set() before calling session_start(). Session upload progress must also still be enabled," the PHP team explained.
PHP has warned of another way an attacker could run code on a web server, two days after it shipped emergency fixes for the critical PHP2Shell flaws. The new issue, assigned CVE-2026-115560, affects only web applications configured in an unusual way, and PHP considers it an unlikely risk.The project is not issuing an emergency fix for it. Instead, it recommends turning off a feature called
AI agents paying for API calls with the x402 SDKs could sign a payment for their full balance of a supported token if a malicious API asked for it, security firm V12 said on October 22. The cause was the SDKs' default client, which set no spending limit until releases on August 18 added one. The risk was limited to agents who automatically signed payments and whose apps set
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