CVE-2026-72225
HighCVSS 7.8Exploitation Probability (EPSS)
Low risk7th percentile - higher than 7% of all known CVEs
Summary
In the Linux kernel's jbd2 module, the function jbd2_journal_initialize_fast_commit() validates journal capacity, but due to an integer underflow on unsigned numbers, the check can be bypassed. This leads to corruption of j_last, j_fc_first, and j_free, resulting in journal abort.
Risk Assessment
The vulnerability could lead to filesystem corruption or system crash, potentially resulting in data loss.
Recommendation
Install the Linux kernel patch that checks num_fc_blks before subtraction and returns -EFSCORRUPTED. Regularly back up data.
Original NVD description (English source)
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.