CVE-2026-63805 Linux CVE debrief

Who should care

Linux kernel users and maintainers, as well as operators, platform administrators, vulnerability management teams, and security teams, should be aware of this vulnerability and ensure they are running the patched kernel version to prevent potential oops or access of bad area errors.

Technical summary

The Linux kernel vulnerability CVE-2026-63805 was caused by a type mismatch in the nx_crypto_ctx_exit function. Specifically, nx_crypto_ctx_shash_exit called nx_crypto_ctx_exit with a crypto_shash_ctx, which is a nx_crypto_ctx *, not a crypto_tfm *. This incorrect type led to a kernel oops when accessing bad areas. The issue was exposed when hardlink(1) opportunistically used AF_ALG. A similar problem existed with nx_crypto_ctx_skcipher_exit, but it hadn't been triggered for years. The vulnerability has a medium defensive priority.

Defensive priority

Medium

Recommended defensive actions

• Apply the kernel patch fixing the nx_crypto_ctx_exit argument issue
• Verify and update Linux kernel versions to ensure the fix is applied
• Monitor system logs for potential oops or access of bad area errors
• 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 record was published on 2026-07-19T12:16:53.230Z and has not been modified since then. The NVD entry is currently Received. There is limited information available about the vulnerability, and defenders should verify the affected scope and severity with the official CVE record and vendor guidance.

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.