CVE-2026-43331x86/kexec: Disable KCOV instrumentation after load_segments()
- 5.5MediumCVSS base score
- 0.12%Exploitation in 30 daysEPSS · top 98% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
In the Linux kernel, the following vulnerability has been resolved: x86/kexec: Disable KCOV instrumentation after load_segments() The load_segments() function changes segment registers, invalidating GS base (which KCOV relies on for per-cpu data). When CONFIG_KCOV is enabled, any subsequent instrumented C code call (e.g. native_gdt_invalidate()) begins crashing the kernel in an endless loop. To reproduce the problem, it's sufficient to do kexec on a KCOV-instrumented kernel: $ kexec -l /boot/otherKernel $ kexec -e The real-world context for this problem is enabling crash dump collection in syzkaller. For this, the tool loads a panic kernel before fuzzing and then calls makedumpfile after the panic. This workflow requires both CONFIG_KEXEC and CONFIG_KCOV to be enabled simultaneously. Adding safeguards directly to the KCOV fast-path (__sanitizer_cov_trace_pc()) is also undesirable as it would introduce an extra performance overhead. Disabling instrumentation for the individual functions would be too fragile, so disable KCOV instrumentation for the entire machine_kexec_64.c and physaddr.c. If coverage-guided fuzzing ever needs these components in the future, other approaches should be considered. The problem is not relevant for 32 bit kernels as CONFIG_KCOV is not supported there. [ bp: Space out comment for better readability. ]
Timeline
ID reserved
By Linux
- 7 days later
· 7 days later
Published
- 42 days later
· 42 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.1 | Medium5.5 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.12% · top 98% of all CVEs (14 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.5.
Affected products
- affected 0d345996e4cb573f8cc81d49b3ee9a7fd2035bef – < 0e96cd314c0d819c1635d68125a4d77852c2162e
- affected 0d345996e4cb573f8cc81d49b3ee9a7fd2035bef – < 593d67032544b9271094fc9b43e437e017cb2b2f
- affected 0d345996e4cb573f8cc81d49b3ee9a7fd2035bef – < 1e3e98596c2769721ade0418434852fb3af4849a
- affected 0d345996e4cb573f8cc81d49b3ee9a7fd2035bef – < de05c66fab8847237a9ca216934e56d3ee837f08
- affected 0d345996e4cb573f8cc81d49b3ee9a7fd2035bef – < 917e3ad3321e75ca0223d5ccf26ceda116aa51e1
- affected 6.6
- unaffected < 6.6
- unaffected 6.6.143 – ≤ 6.6.*
- unaffected 6.12.93 – ≤ 6.12.*
- unaffected 6.18.22 – ≤ 6.18.*
- unaffected 6.19.12 – ≤ 6.19.*
- unaffected 7.0 – ≤ *
References
References5
- https://git.kernel.org/stable/c/0e96cd314c0d819c1635d68125a4d77852c2162e (opens in a new tab)
- https://git.kernel.org/stable/c/593d67032544b9271094fc9b43e437e017cb2b2f (opens in a new tab)
- https://git.kernel.org/stable/c/1e3e98596c2769721ade0418434852fb3af4849a (opens in a new tab)
- https://git.kernel.org/stable/c/de05c66fab8847237a9ca216934e56d3ee837f08 (opens in a new tab)
- https://git.kernel.org/stable/c/917e3ad3321e75ca0223d5ccf26ceda116aa51e1 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-28615 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-43331)Record last updated .