CVE-2026-89644
CVE CVE-2026-89644EUVD EUVD-2026-76556Published 2026-09-11T19:45:36.000Z
What the advisory describes
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.
Source: EUVD (ENISA), in the words of the advisory.
Products the advisory names
These come from the advisory itself, not from any check we performed.
- Linux — Linux 5f9a8a51d8b95505d8de8b7191ae2ed8c504d4af <05a1a816eef8b3e4332620a64fc8cf45c4eb5c0d; patch: 0; 5f9a8a51d8b95505d8de8b7191ae2ed8c504d4af <3f950867c307c5413d628a153ac44915bd117ffd; patch: 7.2.4; 5f9a8a51d8b95505d8de8b7191ae2ed8c504d4af <f42efd634c0ae7ba0ce2fc5e30e291b0803b0ae2; patch: 6.18.50; 4.7; patch: 7.3-rc1
The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.
Carried in the product catalogue
An estate covering these products can be recorded in Patchlage. An advisory about them appears in the next morning's situation report.
- Linux — Linux
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