Linux Kernel up to 6.18.21/6.19.11 load_segments infinite loop

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CTI Interest Score
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5.0$0-$5k0.00

Summaryinfo

A vulnerability classified as critical was found in Linux Kernel up to 6.18.21/6.19.11. This issue affects the function load_segments. The manipulation results in infinite loop. This vulnerability is cataloged as CVE-2026-43331. There is no exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.18.21/6.19.11. Affected is the function load_segments. The manipulation with an unknown input leads to a infinite loop vulnerability. CWE is classifying the issue as CWE-835. The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop. This is going to have an impact on availability. CVE summarizes:

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. ]

The advisory is shared for download at git.kernel.org. This vulnerability is traded as CVE-2026-43331 since 05/01/2026. The exploitability is told to be difficult. There are known technical details, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 321868 (Debian dsa-6355 : ata-modules-6.12.90+deb13-armmp-di - security update), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.18.22 or 6.19.12 eliminates this vulnerability. Applying the patch 1e3e98596c2769721ade0418434852fb3af4849a/de05c66fab8847237a9ca216934e56d3ee837f08/917e3ad3321e75ca0223d5ccf26ceda116aa51e1 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (321868) and CERT Bund (WID-SEC-2026-1454). Once again VulDB remains the best source for vulnerability data.

Affected

  • Google Container-Optimized OS
  • Debian Linux
  • Red Hat Enterprise Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • RESF Rocky Linux
  • Microsoft Azure Linux
  • Open Source Linux Kernel

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.1
VulDB Meta Temp Score: 5.0

VulDB Base Score: 4.8
VulDB Temp Score: 4.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔒

CVSSv2info

AVACAuCIA
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Infinite loop
CWE: CWE-835 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 321868
Nessus Name: Debian dsa-6355 : ata-modules-6.12.90+deb13-armmp-di - security update

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.18.22/6.19.12
Patch: 1e3e98596c2769721ade0418434852fb3af4849a/de05c66fab8847237a9ca216934e56d3ee837f08/917e3ad3321e75ca0223d5ccf26ceda116aa51e1

Timelineinfo

05/01/2026 CVE reserved
05/08/2026 +7 days Advisory disclosed
05/08/2026 +0 days VulDB entry created
06/21/2026 +44 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-43331 (🔒)
GCVE (CVE): GCVE-0-2026-43331
GCVE (VulDB): GCVE-100-362124
CERT Bund: WID-SEC-2026-1454 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 05/08/2026 16:32
Updated: 06/21/2026 21:51
Changes: 05/08/2026 16:32 (58), 05/18/2026 18:13 (11), 06/18/2026 23:17 (7), 06/21/2026 21:51 (2)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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