CVE-2026-43331
Linux kernel: denial of service
- Risk score
- 48/100
- CVSS
- 5.5 v3.1
- Exploit chance (30 days)
- 0.1%
- Published
- 8 May 2026
Open in the live forecast Today's forecast
What to know
- What it is
- 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…
- Affected
- Linux kernel
- Fix
- Apply the vendor's security update; see the linked advisory.
- Exploitation
- No known exploitation
Story map
At a glance
Linux kernel: Amber, patch this week. In the Linux kernel, the following vulnerability has been resolved: ipv6: sr: restore network header before routing and forwarding ipv6_srh_rcv() runs with skb->data at the Segment Routing Header (SRH) while skb_network_header() points at the IPv6 header. When segments_left > 0, ipv6_srh_rcv() previously restored the …
The flaws
- CVE-2026-43331: Denial of service (CVSS 5.5 · EPSS 0%)
- CVE-2026-98096: Out-of-bounds write (CVSS 7.4 · EPSS 1%)
- CVE-2026-98115: Race condition (CVSS 8.8 · EPSS 0%)
- CVE-2026-98117: Use-after-free (CVSS 7.8 · EPSS 0%)
The fix
Fix: Apply the vendor's security update; see the linked advisory.
Who is exposed: Linux kernel
Where it stands
- No known exploitation
How it unfolded
- 6 Nov, Ubuntu security notices (official): USN-9002-1: Linux kernel (NVIDIA Tegra) vulnerabilities
Connects to
- Same weakness: Out-of-bounds write (CWE-787). 399 other warnings in 30 days
- Same product: Earlier Linux kernel warnings. 156 in the last 90 days
Why it is Yellow
- CVSS 5.5 medium
- On your watchlist: linux kernel
- Named in a government or vendor bulletin
Government and vendor bulletins
References
- https://ubuntu.com/security/notices/USN-9002-1
- https://git.kernel.org/stable/c/0e96cd314c0d819c1635d68125a4d77852c2162e
- https://git.kernel.org/stable/c/1e3e98596c2769721ade0418434852fb3af4849a
- https://git.kernel.org/stable/c/593d67032544b9271094fc9b43e437e017cb2b2f
- https://git.kernel.org/stable/c/917e3ad3321e75ca0223d5ccf26ceda116aa51e1
- https://git.kernel.org/stable/c/de05c66fab8847237a9ca216934e56d3ee837f08
Original 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. ]
Last activity 6 Nov 2026. Patch Forecast updates every hour.