In the Linux kernel, the following vulnerability has been resolved: cifs: use cifs_invalidate_cache() in cifs_do_truncate() for O_TRUNC… (CVE-2026-89639)
A vulnerability in the Linux kernel's CIFS implementation related to cache invalidation during file truncation has been resolved. The issue involved improper cache handling in the cifs_do_truncate() function, which could lead to stale cached data being served. The fix involves using cifs_invalidate_cache() to properly invalidate the cache after truncation, ensuring no stale data is returned.
AI Analysis
Technical Summary
The Linux kernel CIFS subsystem had a vulnerability where cifs_do_truncate() was called without holding the i_rwsem lock, preventing the use of cifs_resize_file_locked() for proper fscache cookie resizing. This could cause stale cached data to be served after truncation operations. The resolution was to call cifs_invalidate_cache() after cifs_setsize(), which calls fscache_invalidate() to increment inval_counter and mark the cache as having no valid data, preventing stale data from being served.
Potential Impact
Without proper cache invalidation during truncation, clients could receive stale cached data, potentially leading to data inconsistency or incorrect file contents being read. The vulnerability affects the integrity of cached file data in CIFS mounts.
Mitigation Recommendations
A fix has been implemented in the Linux kernel to call cifs_invalidate_cache() after truncation operations in cifs_do_truncate(). Users should update to the fixed kernel version containing this patch to ensure proper cache invalidation and prevent stale data from being served.
In the Linux kernel, the following vulnerability has been resolved: cifs: use cifs_invalidate_cache() in cifs_do_truncate() for O_TRUNC… (CVE-2026-89639)
Description
A vulnerability in the Linux kernel's CIFS implementation related to cache invalidation during file truncation has been resolved. The issue involved improper cache handling in the cifs_do_truncate() function, which could lead to stale cached data being served. The fix involves using cifs_invalidate_cache() to properly invalidate the cache after truncation, ensuring no stale data is returned.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The Linux kernel CIFS subsystem had a vulnerability where cifs_do_truncate() was called without holding the i_rwsem lock, preventing the use of cifs_resize_file_locked() for proper fscache cookie resizing. This could cause stale cached data to be served after truncation operations. The resolution was to call cifs_invalidate_cache() after cifs_setsize(), which calls fscache_invalidate() to increment inval_counter and mark the cache as having no valid data, preventing stale data from being served.
Potential Impact
Without proper cache invalidation during truncation, clients could receive stale cached data, potentially leading to data inconsistency or incorrect file contents being read. The vulnerability affects the integrity of cached file data in CIFS mounts.
Mitigation Recommendations
A fix has been implemented in the Linux kernel to call cifs_invalidate_cache() after truncation operations in cifs_do_truncate(). Users should update to the fixed kernel version containing this patch to ensure proper cache invalidation and prevent stale data from being served.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-m6p4-6vjr-qq2h
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-89639"]
Threat ID: 6aa4a00455bf5e2cf5a86628
Added to database: 09/12/2026, 00:42:44 UTC
Last enriched: 09/12/2026, 00:57:15 UTC
Last updated: 09/12/2026, 00:57:15 UTC
Views: 2
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