A Linux kernel memory-corruption bug in the 9p client can crash kernels or allow privilege escalation on widely deployed systems; high-impact for most organizations.
CVE-2026-63795
Linux kernel 9p client use-after-free/refcount bug enabling kernel compromise.
Is CVE-2026-63795 being exploited?
Not confirmed. CVE-2026-63795 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.50% probability of exploitation in the next 30 days.
How severe is CVE-2026-63795?
CVE-2026-63795 is rated Critical with a CVSS score of 10.0. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-63795?
Yes. A fix has been recorded for CVE-2026-63795. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-63795 affect?
CVE-2026-63795 affects Linux kernel (9p/Plan9 client). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-63795?
Apply Linux kernel security updates or vendor backports and reboot affected hosts.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Use-after-free/refcount underflow in p9_client_walk can crash the kernel or enable local privilege escalation/arbitrary kernel code execution via crafted 9p walks.
Immediate action required
- affected>= b48dbb998d70b7f48c2ec0a15c3cf47136808e4e and < 99c379ca1e221c3d75c7c804ebbf4e5ee37a3070
- affected>= b48dbb998d70b7f48c2ec0a15c3cf47136808e4e and < b84f46179c806450b89821221ea5bd9a1698aba8
- affected>= b48dbb998d70b7f48c2ec0a15c3cf47136808e4e and < a61bdcba4f64c2f90d01461913f429ab151f1ca6
- affected>= b48dbb998d70b7f48c2ec0a15c3cf47136808e4e and < 6dbe9443d9f5f7fb6d319a7b77108853ae6c6bea
- affected>= b48dbb998d70b7f48c2ec0a15c3cf47136808e4e and < a7656d368265d085ac9bb85ab31b0cdb72ad8c38
- affected>= b48dbb998d70b7f48c2ec0a15c3cf47136808e4e and < 1a3860d46e3eb47dbd60339783cdad7904486b9f
- affected6.0
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.