SB20260912286 - Out-of-bounds write in Linux kernel ocfs2

Description

This security bulletin contains information about 1 vulnerability.

1) Out-of-bounds write (CVE-ID: CVE-2026-89493)

CWE-ID: CWE-787 - Out-of-bounds write

CVSSv4: 4.6 [CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N]

The vulnerability allows a local privileged user to perform out-of-bounds memory reads and writes.

The vulnerability exists due to improper validation of refcount record bounds in ocfs2_validate_refcount_block() when processing crafted refcount blocks during reflink operations. A local privileged user can mount a crafted or corrupted ocfs2 image and issue a reflink operation to perform out-of-bounds memory reads and writes.

A raw write to the block device backing an already-mounted ocfs2 filesystem can also introduce a malicious refcount block.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/04ead708e13ddcb9c39319cbe02a18cef99cb823
• https://git.kernel.org/stable/c/0761d2c9494424469a0d30a9da3496ca010b0b2d
• https://git.kernel.org/stable/c/4ca62df6bc0708947b48da3f6a712ecb8e73929c
• https://git.kernel.org/stable/c/af56e90cb546cb0c47bef059335365283f61d6a4