CVE-2026-46322 Linux CVE debrief

Who should care

Linux system administrators, security teams, and developers responsible for maintaining and securing Linux-based systems should assess exposure and apply patches or updates to fixed versions.

Why it matters

CVE-2026-46322 is a memory leak vulnerability in the Linux kernel's tun driver. Linux system administrators and security teams should assess exposure and apply patches or updates to fixed versions to prevent potential resource exhaustion and denial-of-service conditions.

• Memory leak can cause resource exhaustion
• Potential for denial-of-service (DoS) conditions
• Requires verification of system exposure and patch application

Technical summary

The Linux kernel's tun driver has a vulnerability where a page-frag chunk can be leaked when build_skb() fails in tun_xdp_one(). This can occur for each build_skb() failure in a batch, leading to a memory leak. The issue has been addressed by Linux kernel maintainers. The vulnerability is caused by a missing call to put_page() in the error path of tun_xdp_one(), which leads to a memory leak. The fix involves adding a call to put_page() to free the page in the error path. The vulnerability can be mitigated by applying patches or updates to fixed Linux kernel versions.

Defensive priority

Apply patch or update to fixed version; verify system exposure

Recommended defensive actions

• Apply patch or update to fixed Linux kernel version
• Verify system exposure and review affected versions
• Monitor for potential memory leak issues
• 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
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE Program record and NVD vulnerability detail provide information on the vulnerability. Linux kernel source code references are also available. The issue is caused by a failure to free a page when build_skb() fails in tun_xdp_one(), leading to a memory leak. The Linux kernel maintainers have addressed this issue by adding a call to put_page() in the error path of tun_xdp_one().

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.