CVE-2026-80881: ocfs2: fix buffer head management in ocfs2_read_blocks()

Severity: unknown
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: 2026-09-04 · updated 2026-09-04

Description

In the Linux kernel, the following vulnerability has been resolved: ocfs2: fix buffer head management in ocfs2_read_blocks() In ocfs2_read_blocks(), caller should't assume that buffer head returned by 'sb_getblk()' is exclusively owned and so 'put_bh()' always drops b_count from 1 to 0. If it is not so, buffer head remains on hold and likely to be returned by the next call to 'sb_getblk()' unchanged - that is, with BH_Uptodate bit set even if it has failed validation previously, thus allowing to insert that buffer head into OCFS2 metadata cache and submit it to upper layers. To avoid such a scenario, BH_Uptodate should be cleared immediately after 'validate()' callback has detected some data inconsistency.

Affected products

Linux kernel: from 4.4.204 before 4.5; from 4.9.204 before 4.10; from 4.14.157 before 4.15; from 4.19.87 before 4.20; 4.20 — fixed in 4.10, 4.15, 4.20, 4.5, 7.2

How to fix

Upgrade to a fixed version: Linux kernel 4.10, 4.15, 4.20, 4.5. Check the vendor advisory for mitigations.

References

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