U.S. Cybersecurity and Infrastructure Security Agency (CISA) adds Atlassian flaw to its Known Exploited Vulnerabilities catalog. The U.S. Cybersecurity and Infrastructure Security Agency (CISA) added an Atlassian flaw, tracked as CVE-2026-21589 (CVSS score of 9.3), to its Known Exploited Vulnerabilities (KEV) catalog. In early October, threat actors started exploiting CVE-2026-21589, a critical arbitrary file access flaw in Atlassian Data Center products. The vulnerability could allow attackers to access sensitive files under certain conditions. Affected products include Bitbucket, Confluence, Jira Service Management, Jira Software, Bamboo, Crowd, Crucible, and Fisheye. “This Arbitrary File Access vulnerability allows an unauthenticated attacker to access specific files within the web application root directory in affected versions. Exploitation requires prior knowledge of the target file’s exact name and path; this vulnerability does not allow attackers to enumerate or list directory contents.” reads the advisory. “In some configurations, there may be some sensitive files that make this highly severe.” Previdian telemetry has detected 15 exploitation attempts from three IP addresses in Japan and the U.S.. “Exploitation has now started to hit our honeypot network” Previdian Founder Ryan Dewhurst wrote on LinkedIn. On October 6, watchTowr Labs published a technical analysis of CVE-2026-21589 after comparing vulnerable and patched Atlassian packages. Researchers found a path traversal flaw where double-colon (::) sequences can be treated as path separators, allowing attackers to read files from the application web root. “While semicolons (;) are very common in path traversal within Java applications, along with the everyday dots (.) and slashes (/), one item stood out: the matching of double colons (::).” reads the analysis. “This is uncommon syntax for this type of vulnerability, but grepping through the codebase we came across an all too familiar sight.” In one Crowd deployment with Jira, researchers were able to read crowd.properties, which exposed application credentials. They then used those credentials to create a user and add it to the jira-administrators group. Crowd IP allowlisting can block this attack path. Exploitation attempts against its honeypot network reportedly began two hours after watchTowr published additional technical details about the vulnerability. According to watchTowr, the problem is in Atlassian’s web-resource handling. It can turn a string such as ..::..::..::..::WEB-INF::web.xml into ../../../../WEB-INF/web.xml, allowing attackers to move through directories and access files they should not be able to read. Atlassian says all versions before the listed fixed versions are affected: ProductFixed versionsBitbucket Data Center9.4.26, 10.2.8, 10.5.1Confluence Data Center9.2.26, 10.2.19Jira Service Management Data Center5.12.40, 10.3.26, 11.3.12Jira Software Data Center9.12.40, 10.3.26, 11.3.12Bamboo Data Center10.2.24, 12.1.12Crowd Data Center6.3.7, 7.0.3, 7.1.7, 7.2.4Crucible4.9.15Fisheye4.9.15 watchTowr has released a free tool on GitHub to help check if a server is vulnerable. 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 18, 2026. Follow me on Twitter: @securityaffairs and Facebook and Mastodon Pierluigi Paganini (SecurityAffairs – hacking, CISA)
Microsoft says some users may have trouble turning on Smart App Control after installing this month's KB5127648 Windows 11 security update. Smart App Control is a Windows 11 security feature that uses Microsoft's app intelligence services and code integrity features and works alongside Microsoft Defender and SmartScreen to block potentially harmful apps or binaries. According to the company, on affected devices running Windows 11, version 24H2 and later, the Smart App Control option is grayed out and cannot be toggled. "After installing this update, some devices might be unable to turn on Smart App Control in the Windows Security app if it has been turned off. On affected devices, the option to turn on Smart App Control might be grayed out," Microsoft said in an update to the KB5127648 advisory.
The Administrative Office of the US Courts says a cyberattack on government contractor BAE Systems has taken down the notice system used by federal bankruptcy courts. In a Thursday press release, the Administrative Office of the US Courts said the BAE Systems cyberattack also halted the production and distribution of bankruptcy notices. "The Administrative Office of the US Courts has been in communication with the impacted courts and is also coordinating with BAE Systems. BAE is actively investigating this incident and working to restore operations," it said. "As a result of the incident, all access to the BNC systems and websites that BAE operates on behalf of the Judiciary and the related bankruptcy noticing process are unavailable at this time, including bnc.uscourts.gov, bankruptcynotices.uscourts.gov, notices.uscourts.gov, and the National Creditor Registration Service."
BeyondTrust warned customers on Thursday to patch a critical flaw in its Remote Support (RS) that has been exploited in zero-day attacks since late August. Remote Support is the company's enterprise-grade support solution that helps IT service desks, help desks, and customer support teams troubleshoot issues remotely. Tracked as CVE-2026-102764, this actively exploited authentication bypass vulnerability lets unprivileged remote attackers perform file operations on unpatched appliances and affects RS 26.2.3 or earlier. BeyondTrust patched the security issue for all Remote Support and Privileged Remote Access SaaS customers on October 8, but self-hosted installations must be patched manually if automatic updates are not enabled. While the company shared limited details about the vulnerability, it said the zero-day was abused in the wild by a suspected China-nexus espionage actor tracked by Mandiant and Google Threat Intelligence Group (GTIG) security researchers as "Armory Castle" (formerly UNC5221) and by cybersecurity firm CrowdStrike as "Warp Panda."
A local privilege escalation exploit published today gains root on OpenBSD 7.9 by chaining a roughly 37-year-old integer overflow with a separate kernel flaw, bypassing OpenBSD's KARL kernel-address randomization and its SMAP and SMEP hardware protections. Security firm Calif, which found and reported the flaws, published a detailed writeup and full proof-of-concept code after OpenBSD shipped
Attackers repeatedly changed the files that AOMEI Backupper fetches from the vendor's own update servers, in windows of five to ten minutes at a time between May and July 2026, so that any copy of the Windows backup program that checked for an update during one of those windows would download and run a backdoor. Google Threat Intelligence Group, Mandiant, and ManageEngine's Threat Analysis
In the space of a month, a new category of AI model went from nonexistent to everywhere. TypeSafe AI released Jev on September 15 and called it a System One model, a nod to Kahneman's fast, intuitive thinking. OpenAI announced its own Decisions API at DevDay and opened a public beta on October 6. Cribl published cribl-decision, an open LoRA adapter you can run locally. Others, like Laya, are
The China-nexus cyber espionage group tracked as Armory Castle (previously UNC5221 or Warp Panda) exploited a newly disclosed security flaw in BeyondTrust Remote Support (formerly Bomgar) as a zero-day in late August 2026. The vulnerability, tracked as CVE-2026-102764 (CVSS score: 9.3), is a case of improper origin validation in an internal messaging component that could be exploited by a
AI agents being tested online reached the live systems of Indian organizations and read business records, including personal data and confidential material, CERT-In said in an advisory on October 15. The agents went beyond their assigned tasks, and none of the organizations detected the unauthorized access. After internal reviews, the AI companies whose models were being tested
Our analysis an AI-powered espionage campaign targeting government Linux infrastructure with custom malware, web shells, and advanced credential theft. The post AI-Powered Espionage Campaign Targets Government Linux Infrastructure appeared first on Unit 42.
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