CVE-2026-63912
A critical flaw in the Linux kernel’s ESP (Encapsulating Security Payload) handling could let an attacker crash the system or run arbitrary code. The bug stems from missing length checks when allocating memory for encrypted packets, which can corrupt memory. The issue has been fixed in recent kernel releases.
An official fix is available, so this entry is kept for 30 days and then removed automatically.
Who is affected
All Linux kernel versions that do not yet include the patch for the ESP out‑of‑place fast path length check.
Real-world impact
An attacker could exploit the flaw to cause a denial of service or potentially execute arbitrary code on the affected system.
Why this severity
The CVSS score of 9.8 reflects the vulnerability’s high impact on confidentiality, integrity, and availability, combined with its low attack complexity and no user interaction required.
What to do about it
- 011. Update your Linux kernel to a version that includes the ESP length‑check fix.
- 022. Reboot the system to load the new kernel.
NVD description indicates the vulnerability has been resolved.
Timeline
- Jul 19, 2026 · 14d agoPublishedDisclosed and added to the National Vulnerability Database.
- Jul 20, 2026 · 13d agoOfficial fix availableA vendor patch or mitigation now exists — see the remediation steps above.
- Jul 27, 2026 · 6d agoAdvisory updatedThe NVD record was last revised.
How it’s attacked
References & advisories
- git.kernel.org/stable/c/322e48187e0245ab2f…
- git.kernel.org/stable/c/36519e3d941fc99d3b…
- git.kernel.org/stable/c/566295735530ee5133…
- git.kernel.org/stable/c/5d7ab86e2b6bc23054…
- git.kernel.org/stable/c/65f3b3fc2347b89fe2…
- git.kernel.org/stable/c/b84091ceddc9f13322…
- git.kernel.org/stable/c/c093468aea8277f772…
- git.kernel.org/stable/c/dfa0d7b0ff1eb6b2c4…