CVE-2023-53526: jbd2: check 'jh->b_transaction' before removing it from checkpoint

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-10-01 · updated 2026-10-15

Description

In the Linux kernel, the following vulnerability has been resolved: jbd2: check 'jh->b_transaction' before removing it from checkpoint Following process will corrupt ext4 image: Step 1: jbd2_journal_commit_transaction __jbd2_journal_insert_checkpoint(jh, commit_transaction) // Put jh into trans1->t_checkpoint_list journal->j_checkpoint_transactions = commit_transaction // Put trans1 into journal->j_checkpoint_transactions Step 2: do_get_write_access test_clear_buffer_dirty(bh) // clear buffer dirty，set jbd dirty __jbd2_journal_file_buffer(jh, transaction) // jh belongs to trans2 Step 3: drop_cache journal_shrink_one_cp_list jbd2_journal_try_remove_checkpoint if (!trylock_buffer(bh)) // lock bh, true if (buffer_dirty(bh)) // buffer is not dirty __jbd2_journal_remove_checkpoint(jh) // remove jh from trans1->t_checkpoint_list Step 4: jbd2_log_do_checkpoint trans1 = journal->j_checkpoint_transactions // jh is not in trans1->t_checkpoint_list jbd2_cleanup_journal_tail(journal) // trans1 is done Step 5: Power cut, trans2 is not committed, jh is lost in next mounting. Fix it by checking 'jh->b_transaction' before remove it from checkpoint.

Affected products

Linux kernel: from 5.15.129 before 5.15.132; from 6.1.50 before 6.1.54; from 6.4.13 before 6.5; from 6.5.1 before 6.5.4; 6.5, 6.5-rc3, 6.5-rc4, 6.5-rc5, 6.5-rc6, 6.5-rc7 — fixed in 5.15.132, 6.1.54, 6.5, 6.5.4

How to fix

Upgrade to a fixed version: Linux kernel 5.15.132, 6.1.54, 6.5, 6.5.4. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2023-53526 or the next vulnerability affects your stack