CVE-2026-49414 FreeBSD CVE debrief

Who should care

System administrators and security teams responsible for managing Linux and potentially other Unix-like systems should be aware of this vulnerability. Given its high severity and the potential for exploitation, priority should be given to assessing and mitigating this vulnerability, especially in environments where unprivileged local users may pose a risk. This includes reviewing system configurations, ensuring timely application of patches, and monitoring for potential exploitation attempts.

Technical summary

The ELF image activator's handling of ASLR (Address Space Layout Randomization) preference flags for setuid binaries was flawed. Normally, ASLR is used to randomize the base address of a process's memory space, making it harder for attackers to predict where vulnerable code is located. However, due to this vulnerability, an unprivileged local user could effectively disable ASLR for a setuid PIE (Position-Independent Executable) binary. This was possible because the ASLR preference flags were cleared after, rather than before, the computation of the PIE base address. As a result, if a user requested ASLR to be disabled via procctl(2) before executing the binary with execve(2), this preference would still be in effect when the base address was chosen, bypassing ASLR protections. This significantly eases the exploitation of any memory corruption vulnerabilities in the affected binaries, as the memory layout is now predictable.

Defensive priority

High priority should be given to patching or mitigating this vulnerability. Given its nature, allowing an unprivileged local user to disable ASLR protections, it poses a significant risk to systems where such users may have access.

Recommended defensive actions

• Assess the vulnerability's impact on your systems and prioritize patching.
• Apply patches or updates provided by the vendor as soon as possible.
• Review system configurations to ensure ASLR protections are enabled and not being bypassed through other means.
• Monitor system logs and network traffic for potential exploitation attempts.
• Consider implementing additional security controls, such as restricting the execution of setuid binaries or enhancing monitoring and logging for suspicious activity.

Evidence notes

The CVE record and NVD detail provide official information about the vulnerability. A reference from [email protected] suggests a potential connection to FreeBSD, though the vendor is listed as Unknown Vendor. The vulnerability's details and impact are based on the information available from these sources.

Official resources