CVE-2026-43266

Description

In the Linux kernel, the following vulnerability has been resolved: EFI/CPER: don't go past the ARM processor CPER record buffer There's a logic inside GHES/CPER to detect if the section_length is too small, but it doesn't detect if it is too big. Currently, if the firmware receives an ARM processor CPER record stating that a section length is big, kernel will blindly trust section_length, producing a very long dump. For instance, a 67 bytes record with ERR_INFO_NUM set 46198 and section length set to 854918320 would dump a lot of data going a way past the firmware memory-mapped area. Fix it by adding a logic to prevent it to go past the buffer if ERR_INFO_NUM is too big, making it report instead: [Hardware Error]: Hardware error from APEI Generic Hardware Error Source: 1 [Hardware Error]: event severity: recoverable [Hardware Error]: Error 0, type: recoverable [Hardware Error]: section_type: ARM processor error [Hardware Error]: MIDR: 0xff304b2f8476870a [Hardware Error]: section length: 854918320, CPER size: 67 [Hardware Error]: section length is too big [Hardware Error]: firmware-generated error record is incorrect [Hardware Error]: ERR_INFO_NUM is 46198 [ rjw: Subject and changelog tweaks ]

CVSS v3.1 Score

5.5

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS — Exploit Prediction

0.0001

Probability of exploitation

0.02%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Affected Products

Vendor	Product	Versions
linux	linux_kernel	4.13 — 5.10.252
linux	linux_kernel	5.11 — 5.15.202
linux	linux_kernel	5.16 — 6.1.165
linux	linux_kernel	6.2 — 6.6.128
linux	linux_kernel	6.7 — 6.12.75
linux	linux_kernel	6.13 — 6.18.16
linux	linux_kernel	6.19 — 6.19.6

References

Advisories & Patches

https://git.kernel.org/stable/c/25b290624b0e3d2f0f90238709ee0b6009b9fde8 https://git.kernel.org/stable/c/45766863baf899059e75595dd3cb1116467f2095 https://git.kernel.org/stable/c/64eb63f573f497553e1a0c388bbcdd639e0f0704 https://git.kernel.org/stable/c/a68d22902a6916e10ee235fee609239004e129d0 https://git.kernel.org/stable/c/be10c1bdf64a39832998f54900aa309b3917abcf https://git.kernel.org/stable/c/c80113dcfc807308f5ab33847fae77e07531aeb8 https://git.kernel.org/stable/c/ca2aad8771aa9091bc9e42e7d546bd40b72ddcd4 https://git.kernel.org/stable/c/eae21beecb95a3b69ee5c38a659f774e171d730e

Frequently Asked Questions

What is CVE-2026-43266? +

In the Linux kernel, the following vulnerability has been resolved: EFI/CPER: don't go past the ARM processor CPER record buffer There's a logic inside GHES/CPER to detect if the section_length is too small, but it doesn't detect if it is too big. Currently, if the firmware receives an ARM processor CPER record stating that a section length is big, kernel will blindly trust section_length, producing a very long dump. For instance, a 67 bytes record with ERR_INFO_NUM set 46198 and section length set to 854918320 would dump a lot of data going a way past the firmware memory-mapped area. Fix it by adding a logic to prevent it to go past the buffer if ERR_INFO_NUM is too big, making it report instead: [Hardware Error]: Hardware error from APEI Generic Hardware Error Source: 1 [Hardware Error]: event severity: recoverable [Hardware Error]: Error 0, type: recoverable [Hardware Error]: section_type: ARM processor error [Hardware Error]: MIDR: 0xff304b2f8476870a [Hardware Error]: section length: 854918320, CPER size: 67 [Hardware Error]: section length is too big [Hardware Error]: firmware-generated error record is incorrect [Hardware Error]: ERR_INFO_NUM is 46198 [ rjw: Subject and changelog tweaks ] It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2026-43266? +

CVE-2026-43266 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0001, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-43266? +

CVE-2026-43266 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-43266? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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