CVE-2026-72225
In the Linux kernel, the following vulnerability has been resolved: jbd2: fix integer underflow in jbd2_journal_initialize_fast_commit() jbd2_journal_initialize_fast_commit() validates journal capacity by checking (journal->j_last - num_fc_blks <…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.18%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
In the Linux kernel, the following vulnerability has been resolved: jbd2: fix integer underflow in jbd2_journal_initialize_fast_commit() jbd2_journal_initialize_fast_commit() validates journal capacity by checking (journal->j_last - num_fc_blks < JBD2_MIN_JOURNAL_BLOCKS). Both j_last and num_fc_blks are unsigned, so when num_fc_blks exceeds j_last the subtraction wraps to a large value, bypassing the bounds check. The resulting underflow corrupts j_last, j_fc_first, and j_free, leading to journal abort. Fix by checking num_fc_blks against j_last before the subtraction, returning -EFSCORRUPTED.
- CVSS 3.1
- 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.18% probability · 7th percentile
- CISA KEV
- Not listed
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/289a2ca0c9b7eae74f93fc213b0b971669b8683d
- https://git.kernel.org/stable/c/4450dcaadf7d4aae8b6e4223b5d6ee4eb77097a9
- https://git.kernel.org/stable/c/4b48dcb88bb9117e3d3f051175a9a8b7cff7f8b6
- https://git.kernel.org/stable/c/78955fdce8ff654e6d33a2fa90882a1e7eb26330
- https://git.kernel.org/stable/c/a58fc10adf503969fec2007b5afe8987258046c4
- https://git.kernel.org/stable/c/aa90f00932bf572d6ef284c977c2a60b39c13bd6
- https://git.kernel.org/stable/c/e144ad0250f77e23e28949587b8b57e40dc3b512
- https://git.kernel.org/stable/c/fb9b49618ed7296ebfad62a3835da8945f727001
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.