CVE-2026-89644btrfs: fix extent map leak in NOCOW direct I/O write
Updated under an hour ago ()
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In the Linux kernel, the following vulnerability has been resolved: btrfs: fix extent map leak in NOCOW direct I/O write btrfs_dio_iomap_begin() calls btrfs_get_extent(), which returns an extent map reference that must be dropped on all exit paths. For direct writes into a NOCOW range, btrfs_get_blocks_direct_write() keeps using that extent map and asks btrfs_create_dio_extent() to allocate the ordered extent. If that fails, for example because btrfs_alloc_ordered_extent() fails, the function returns the error without dropping the input extent map. The PREALLOC path avoided this by dropping the input extent map before replacing it with the newly created one. Check the error from btrfs_create_dio_extent() before replacing the map and drop the input extent map on failure.
- CVSS
- Not yet scored
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Received
- Record last updated
- Sep 21, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from 5f9a8a51d8b95505d8de8b7191ae2ed8c504d4af before b7c873765875645b11503f94c9bae2ca80127375; from 5f9a8a51d8b95505d8de8b7191ae2ed8c504d4af before f42efd634c0ae7ba0ce2fc5e30e291b0803b0ae2; 5f9a8a51d8b95505d8de8b7191ae2ed8c504d4af builds before 05a1a816eef8b3e4332620a64fc8cf45c4eb5c0d; 5f9a8a51d8b95505d8de8b7191ae2ed8c504d4af builds before 3f950867c307c5413d628a153ac44915bd117ffd | CNA record |
References
- https://git.kernel.org/stable/c/b7c873765875645b11503f94c9bae2ca80127375
- https://git.kernel.org/stable/c/f42efd634c0ae7ba0ce2fc5e30e291b0803b0ae2
- https://git.kernel.org/stable/c/05a1a816eef8b3e4332620a64fc8cf45c4eb5c0d
- https://git.kernel.org/stable/c/3f950867c307c5413d628a153ac44915bd117ffd
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.