OpenBSD flaws, including a 37-year-old BSD bug, enable local attackers to bypass security protections and gain root access. Patches are available. Cybersecurity firm Calif published a full exploit and write-up this week for a local privilege escalation on OpenBSD 7.9 that chains two separate kernel flaws, one of them a 37-year-old integer overflow inherited from the original BSD sources. The exploit bypasses OpenBSD’s KARL address randomization and the SMAP and SMEP hardware protections without needing any information disclosure vulnerability at all. OpenBSD already shipped patches for both issues in September: the integer overflow fix in errata 018 on September 14, and the related use-after-free fix in errata 026 on September 30. Both are available through syspatch and cover all architectures. The shared memory attachment counter, shm_nattch, was defined as a signed 16-bit integer in BSD source code in 1988. It could hold a maximum value of 32,767. OpenBSD inherited this definition and never changed it. By mapping 127 shared memory segments and creating 259 processes through forking, an attacker can push the counter beyond its limit, causing it to wrap around to a negative value. This triggers a use-after-free vulnerability through a race condition. The corrupted counter makes the kernel free memory that other processes are still using. The second flaw builds on the first. An out-of-bounds write overwrites multicast membership counters in the kernel. When the affected socket closes, the resulting counter updates modify page table entries, allowing user memory to be accessed with supervisor-level privileges. This bypasses SMAP and SMEP protections by exploiting errors in the kernel’s internal memory accounting, rather than directly attacking the hardware. “One traced back roughly 37 years to the original BSD sources, where a shared memory attachment counter was defined as a signed 16-bit short. Repeatedly forking a process with shared memory attachment records could push that counter past its maximum value of 32,767, causing it to wrap to a negative value.” reads the Califs’ analysis. “This integer overflow could lead to a use-after-free via a race condition; combined with a separate out-of-bounds write in the kernel, it allowed local privilege escalation to root.” OpenBSD’s KARL protection relinks the kernel at boot to randomize function and data addresses, which is real and meaningful hardening. “While OpenBSD’s KARL relinks the kernel binary to randomize both function and data addresses, the kernel’s memory allocators remain deterministic. Both the boot-time allocator and the best-fit allocator lack base address randomization.” continues the analysis. “Consequently, early boot allocations consistently land at predictable locations across boots on the same hardware.” Early boot allocations, including function pointers in network interface handlers, land at the same addresses across every reboot on the same hardware. That predictability is what the exploit actually uses. It targets the lo0 and enc0 interface ioctl handlers, two structures the kernel always places at known addresses, overwriting one to gain code execution and using the other to cleanly restore the overwritten pointer afterward. No information disclosure needed, no guessing required. The researchers used kernel memory allocation metrics available through sysctl to track live allocations and detect when new pages were being created, essentially doing heap layout analysis from userland. They aligned IP socket allocations and set a multicast TTL option to a non-default value to get a persistent 16-byte structure placed where they needed it. The race condition was won by using IPC_RMID in one process while a helper process running in parallel attached a size-confused shared memory segment. Calif researchers note there’s no evidence of either flaw being exploited in the wild, and no CVE has been assigned to either issue as of publication. The report does more than explain the exploit. Calif suggests four security improvements that could make this attack much harder or prevent it entirely. First, safe-unlinking for kernel linked lists checks that data structures are valid before writing to memory. If something is wrong, the kernel stops. FreeBSD and NetBSD already use this protection, but OpenBSD does not. Second, randomizing the page table’s self-referential mapping at boot would prevent attackers from predicting which memory location to target with the decrement operation. Third, randomizing the kernel allocator’s base address at boot would make it harder to predict function pointer locations. The researchers say this protection would have almost no performance cost. Finally, enabling array bounds checks in release builds would detect this type of out-of-bounds write. Calif also reported 21 issues to FreeBSD that the same protection could have caught, including flaws that could allow local privilege escalation. Follow me on Twitter: @securityaffairs and Facebook and Mastodon Pierluigi Paganini (SecurityAffairs – hacking, OpenBSD)
Microsoft has confirmed that this month's Windows Server security updates are causing OWA sign-in and mail delivery issues on some Exchange Server systems. In a new Windows release health dashboard update over the weekend, Microsoft said users may have trouble accessing email or signing in to Outlook after installing the latest updates on systems running Windows Server 2019 and later. In some cases, affected customers are also reportedly seeing Exchange Server OWA failing with a "MapiExceptionMdbOffline: Unable to make connection to the server. (hr=0x80004005, ec=1142)" error and Event ID 1006 in the application log. "After installing the October 2026 Windows security update [..], some on-premises Exchange servers might experience issues accessing or sending email. Users might be unable to sign in to Outlook on the web (OWA), or email messages sent from Outlook might remain in the Outbox and not be delivered. Additionally, Exchange might experience issues accessing mailboxes during mailbox replication," it said.
Attackers are exploiting vulnerability CVE-2026-106931 in SiteGuard Server Edition to run commands as root or SYSTEM. EG Secure Solutions published an urgent alert warning of CVE-2026-106931, an OS command injection bug in SiteGuard Server Edition. Threat actors are already exploiting it in the wild. A successful exploit lets them run commands with root or SYSTEM privileges on the server where the product runs. SiteGuard is a Japanese web application firewall (WAF) that runs directly on the web server it protects. The vulnerability affects its statistics feature, which is enabled by default. The vendor and JVN rated the vulnerability with a CVSS 4.0 score of 8.5 and a CVSS 3.0 score of 7.8. An attacker needs local access and low-level privileges to exploit this vulnerability. This suggests the flaw may be used after an attacker has already gained access to a system. The vulnerability impacts version 2.20 or later. On Apache, Nginx and IIS that means anything before 8.00 Update 5, except FreeBSD, and on FreeBSD with Apache or Nginx it means anything before 7.00 Update 6. IIS editions from 3.10 through 4.00 Update 4 aren’t affected, and only installs with the statistics function enabled are exposed. For people who can’t upgrade their version, the vendor offers a patch that replaces the files used in statistics processing, and it covers end-of-life versions too. Be aware that updating or patching can erase the traces of an attack, so the vendor tells administrators to download the diagnostic information first. “Before updating, please be sure to download and save your “Diagnostic Information” (as this may erase traces of the attack).” reads the vendor’s advisory. In the web management screen that’s the diagnostic information page, then the download option. Do it before you touch anything, because a clean server after the update doesn’t prove it was clean before. The timeline is short, but not everyone was warned at the same time. The vendor says it notified customers with direct support contracts on September 29. The public alert and the JVN advisory were published on October 14. The vendor reported the vulnerability to Japan’s IPA, while JPCERT/CC coordinated the disclosure and published its own alert. Customers without direct support contracts received the warning about two weeks later. Many details remain unknown. Neither advisory identifies the attackers or victims, explains how the attacks were carried out, or says how many systems were affected. The vendor has confirmed that the vulnerability has been exploited. If you use this product, check your systems for signs of compromise and investigate any suspicious activity. Follow me on Twitter: @securityaffairs and Facebook and Mastodon Pierluigi Paganini (SecurityAffairs – hacking, SiteGuard WAF)
Threat actors have begun to exploit a chain of vulnerabilities in Plex Media Server to deploy cryptocurrency miners and reverse proxy software, a day after a proof-of-concept (PoC) went public. According to a researcher who goes by the online alias boredhackerblog, the exploitation activity involves chaining four different vulnerabilities, collectively called Plex2Shell. The vulnerabilities
Copies of Rank Math PRO, the paid version of the Rank Math SEO plugin for WordPress, that were downloaded from rankmath.com or delivered as updates between 20:02 UTC on October 15 and 07:12 UTC on October 16 contained malware, Rank Math said in a security notice published on October 16. Any site that installed and activated one of those copies should be treated as compromised, and the
The worst problems don't always come with a warning. Sometimes they arrive through a service everyone trusts, a device someone bought, or a system nobody thought to check. By the time something looks wrong, the damage may already be done. This week had plenty of that. Trusted connections became a problem. Hardware wasn't as safe as it looked. Old bugs found new victims, and some systems were
The threat actor behind the GhostAction supply chain attack has expanded beyond injecting malicious GitHub Actions workflows into compromised projects to phish open-source developers and deliver a stealer malware disguised within a fake font file. The latest evolution, detailed by OpenSourceMalware, signals that the attackers are actively refining their modus operandi in response to steps
In Salesforce Agentforce, the recommended way to make an agent respond to events is a Flow: a record is created or a case is updated, and the Flow passes data into the agent's prompt. Separately, Email-to-Case and Web-to-Case turn inbound customer messages into case records; it is how airlines and hotels run support intake. Both are standard, documented, as-designed features. Chained together,
A fake Web3 accelerator has been observed pushing information stealers and backdoors to Windows and macOS systems using malicious npm packages under the pretext of offering free artificial intelligence (AI) credits for Anthropic Claude and Google Gemini, coding tools, and security audits. "The tools delivered information-stealing malware and backdoors for macOS and Windows machines," Elastic
An intruder reached a legacy system at OpenCode on the night of October 16 and may have exposed the third-party AI provider keys that users had saved in OpenCode Console, the company said. Console is OpenCode's optional hosted service: a workspace saves its own OpenAI, Anthropic, or Google key there, and Console uses that key to call the provider so team members can use the models without
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