Linux: Use After Free
CVE-2026-45861 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 53aaf083de197946b25bc4ffa3068d37366ce73d, ca7c67bdd293089b3483f18886d6b2d0037d2ad9, 1d47922b98046b8070a77347fb883a6523792803 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.19% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 53aaf083de197946b25bc4ffa3068d37366ce73d or ca7c67bdd293089b3483f18886d6b2d0037d2ad9 or 1d47922b98046b8070a77347fb883a6523792803 or 80fff26d7a0c3926b511661c27eecc811a420eef, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.12.75 or 6.18.14 or 6.19.4, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | a475c5dd16e57c570113eccba51955b5df8bb052 up to, but not including, 53aaf083de197946b25bc4ffa3068d37366ce73d; a475c5dd16e57c570113eccba51955b5df8bb052 up to, but not including, ca7c67bdd293089b3483f18886d6b2d0037d2ad9; a475c5dd16e57c570113eccba51955b5df8bb052 up to, but not including, 1d47922b98046b8070a77347fb883a6523792803; a475c5dd16e57c570113eccba51955b5df8bb052 up to, but not including, 80fff26d7a0c3926b511661c27eecc811a420eef; a475c5dd16e57c570113eccba51955b5df8bb052 up to, but not including, 22150a7d401d9e9169b9b68e05bed95f7f49bf69; 6.6 | 53aaf083de197946b25bc4ffa3068d37366ce73d, ca7c67bdd293089b3483f18886d6b2d0037d2ad9, 1d47922b98046b8070a77347fb883a6523792803, 80fff26d7a0c3926b511661c27eecc811a420eef, 22150a7d401d9e9169b9b68e05bed95f7f49bf69 |
| Linux | Linux Kernel | 6.6 up to, but not including, 6.12.75; 6.13 up to, but not including, 6.18.14; 6.19 up to, but not including, 6.19.4 | 6.12.75, 6.18.14, 6.19.4 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.
Official description
In the Linux kernel, the following vulnerability has been resolved: gfs2: Fix slab-use-after-free in qd_put Commit a475c5dd16e5 ("gfs2: Free quota data objects synchronously") started freeing quota data objects during filesystem shutdown instead of putting them back onto the LRU list, but it failed to remove these objects from the LRU list, causing LRU list corruption. This caused use-after-free when the shrinker (gfs2_qd_shrink_scan) tried to access already-freed objects on the LRU list. Fix this by removing qd objects from the LRU list before freeing them in qd_put(). Initial fix from Deepanshu Kartikey <[email protected]>.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other references
Recent Use After Free vulnerabilities
- 8.1 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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