CVE-2024-41086: bcachefs: Fix sb_field_downgrade validation

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-07-29 · updated 2026-08-04

Description

In the Linux kernel, the following vulnerability has been resolved: bcachefs: Fix sb_field_downgrade validation - bch2_sb_downgrade_validate() wasn't checking for a downgrade entry extending past the end of the superblock section - for_each_downgrade_entry() is used in to_text() and needs to work on malformed input; it also was missing a check for a field extending past the end of the section

Affected products

Linux kernel: from 6.7.1 before 6.9.8; 6.7 — fixed in 6.9.8

How to fix

Upgrade to a fixed version: Linux kernel 6.9.8. Check the vendor advisory for mitigations.

References

https://git.kernel.org/stable/c/692aa7a54b2b28d59f24b3bf8250837805484b99
https://git.kernel.org/stable/c/bf920ed92ef24dcd6970c88881cd4700b3acf05b
https://git.kernel.org/stable/c/692aa7a54b2b28d59f24b3bf8250837805484b99
https://git.kernel.org/stable/c/bf920ed92ef24dcd6970c88881cd4700b3acf05b

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