Medium [CVE-2026-74349] reject FITRIM ranges shorter than a cluster
This medium-severity Red Hat Linux advisory covers CVE-2026-74349.
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Summary
In the Linux kernel, the following vulnerability has been resolved: ocfs2: reject FITRIM ranges shorter than a cluster ocfs2_trim_mainbm() trims the global bitmap in cluster units, but its too-short range validation only checks sb->s_blocksize.
On filesystems with a cluster size larger than the block size, a FITRIM range that is at least one block but shorter than one cluster is accepted and shifted down to len == 0. The later start + len - 1 and len -=... arithmetic then underflows and can drive trimming past the requested range.
That preserves the existing -EINVAL behavior for requests that cannot discard even one allocation unit and keeps zero-cluster trims out of the group walk. A flaw was found in the Linux kernel's OCFS2 (Oracle Cluster File System version 2) component.
A local attacker with appropriate permissions could trigger an issue during filesystem trimming operations. By providing a specific range for trimming that is smaller than expected, an internal calculation error (integer underflow) occurs.
This error could cause the system to trim data outside the intended area, potentially leading to data corruption or making the system unavailable (Denial of Service). Red Hat severity: Moderate — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H).
Weakness: CWE-787.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · medium-confidence parse· fetched 16 days ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 16 days ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 16 days ago·verify at source
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