CVE-2024-26685: Debian Linux

Medium severity, CVSS 5.5. EPSS: 0.3% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: nilfs2: fix potential bug in end_buffer_async_write According to a syzbot report, end_buffer_async_write(), which handles the completion of block device writes, may detect abnormal condition of the buffer async_write flag and cause a BUG_ON failure when using nilfs2. Nilfs2 itself does not use end_buffer_async_write(). But, the async_write flag is now used as a marker by commit 7f42ec394156 ("nilfs2: fix issue with race condition of competition between segments for dirty blocks") as a means of resolving double list insertion of dirty blocks in nilfs_lookup_dirty_data_buffers() and nilfs_lookup_node_buffers() and the resulting crash. This modification is safe as long as it is used for file data and b-tree node blocks where the page caches are independent. However, it was irrelevant and redundant to also introduce async_write for segment summary and super root blocks that share buffers with the backing device. This led to the possibility that the BUG_ON check in end_buffer_async_write would fail as described above, if independent writebacks of the backing device occurred in parallel. The use of async_write for segment summary buffers has already been removed in a previous change. Fix this issue by removing the manipulation of the async_write flag for the remaining super root block buffer.

Affected products

• Debian Debian Linux: version 10.0 only
• Linux Linux Kernel: from 3.2.52, before 3.3 (fixed in 3.3); from 3.4.83, before 3.5 (fixed in 3.5); from 3.10.16, before 3.11 (fixed in 3.11); from 3.11.5, before 4.19.307 (fixed in 4.19.307); from 4.20, before 5.4.269 (fixed in 5.4.269); from 5.5, before 5.10.210 (fixed in 5.10.210); …

Published 2024-04-03. Last modified 2026-06-17.