CVE-2024-49957: ocfs2: fix null-ptr-deref when journal load failed.

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-10-21 · updated 2026-06-17
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: ocfs2: fix null-ptr-deref when journal load failed. During the mounting process, if journal_reset() fails because of too short journal, then lead to jbd2_journal_load() fails with NULL j_sb_buffer. Subsequently, ocfs2_journal_shutdown() calls jbd2_journal_flush()->jbd2_cleanup_journal_tail()-> __jbd2_update_log_tail()->jbd2_journal_update_sb_log_tail() ->lock_buffer(journal->j_sb_buffer), resulting in a null-pointer dereference error. To resolve this issue, we should check the JBD2_LOADED flag to ensure the journal was properly loaded. Additionally, use journal instead of osb->journal directly to simplify the code.

Affected products

Linux kernel: from 2.6.32 before 5.10.227; from 5.11 before 5.15.168; from 5.16 before 6.1.113; from 6.2 before 6.6.55; from 6.7 before 6.10.14; from 6.11 before 6.11.3 — fixed in 5.10.227, 5.15.168, 6.1.113, 6.10.14, 6.11.3, 6.6.55

How to fix

Upgrade to a fixed version: Linux kernel 5.10.227, 5.15.168, 6.1.113, 6.10.14. Check the vendor advisory for mitigations.

References

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