CVE-2026-46158 Linux CVE debrief

Who should care

Linux kernel maintainers and users, particularly those using MPTCP, should assess their exposure and apply patches as necessary to prevent potential resource leaks. This includes verifying the affected versions of the Linux kernel, reviewing compensating controls, and monitoring for potential exploitation attempts. The vulnerability can impact operators, platforms, and security teams, so it is essential to review the official advisory and take necessary

Why it matters

A potential memory leak vulnerability was found in the Linux kernel's MPTCP implementation. While the CVSS score is relatively low, Linux kernel maintainers and users should assess their exposure and apply patches as necessary to prevent potential resource leaks.

• Verify socket reference count handling in MPTCP implementation
• Assess exposure to potential resource leak vulnerability
• Apply patches to resolve the issue

Technical summary

The Linux kernel's MPTCP implementation has a potential memory leak vulnerability. When an ADD_ADDR is retransmitted, the socket reference count is not properly decremented in all cases, leading to a potential resource leak. Patches have been provided to resolve the issue by ensuring that the socket reference count is properly decremented. Linux kernel maintainers and users should assess their exposure and apply patches as necessary to prevent potential resource leaks. The vulnerability requires specific conditions to be triggered and has a relatively low CVSS score, but it is still important to address to prevent potential resource exhaustion.

Defensive priority

Medium priority for Linux kernel maintainers and users, as the vulnerability requires specific conditions to be triggered and has a relatively low CVSS score.

Recommended defensive actions

• Review and apply patches provided by the Linux kernel maintainers
• Verify the affected versions of the Linux kernel and update accordingly
• Monitor for potential exploitation attempts
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The vulnerability was introduced in the Linux kernel and has been resolved with patches provided. The affected versions require verification from the supplied official sources. To verify the vulnerability, defenders should review the official advisory, assess the affected scope, and apply patches as necessary. The patches address the potential memory leak by ensuring that the socket reference count is properly decremented in all cases.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.