Linux: Use After Free
CVE-2026-64343 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 fc55923a972e715f9a27187b47d4920709e23d85, e5a9bdce4bfd3e2226b5f3df5fb8385d6935ee69, af59829e67e11ba2511a9f8e4b9111afc7d1f550 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 0.13% 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 fc55923a972e715f9a27187b47d4920709e23d85 or e5a9bdce4bfd3e2226b5f3df5fb8385d6935ee69 or af59829e67e11ba2511a9f8e4b9111afc7d1f550 or 02ca08fff74cf9b0a3c4d2cacde1c6edeeb95bb4, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.261 or 5.15.212 or 6.1.178 or 6.6.145, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | ce0d7d3f575fc1ba6a89c3c651e710355590daff up to, but not including, fc55923a972e715f9a27187b47d4920709e23d85; ce0d7d3f575fc1ba6a89c3c651e710355590daff up to, but not including, e5a9bdce4bfd3e2226b5f3df5fb8385d6935ee69; ce0d7d3f575fc1ba6a89c3c651e710355590daff up to, but not including, af59829e67e11ba2511a9f8e4b9111afc7d1f550; ce0d7d3f575fc1ba6a89c3c651e710355590daff up to, but not including, 02ca08fff74cf9b0a3c4d2cacde1c6edeeb95bb4; ce0d7d3f575fc1ba6a89c3c651e710355590daff up to, but not including, d8f69404e1d671326f86d378b9f5bfbd56490e9d; ce0d7d3f575fc1ba6a89c3c651e710355590daff up to, but not including, 2107a4fc8ff1cf1d52f416c1e5cc8e97413a5915; ce0d7d3f575fc1ba6a89c3c651e710355590daff up to, but not including, a3e794136ab5e3ad1e7019175a4b837aec86db4b; ce0d7d3f575fc1ba6a89c3c651e710355590daff up to, but not including, 19bdfc7b3c179331eafa423d87e1336f43bbfeb8; and 1 more ranges | fc55923a972e715f9a27187b47d4920709e23d85, e5a9bdce4bfd3e2226b5f3df5fb8385d6935ee69, af59829e67e11ba2511a9f8e4b9111afc7d1f550, 02ca08fff74cf9b0a3c4d2cacde1c6edeeb95bb4, d8f69404e1d671326f86d378b9f5bfbd56490e9d, 2107a4fc8ff1cf1d52f416c1e5cc8e97413a5915 |
| Linux | Linux Kernel | 2.6.26 up to, but not including, 5.10.261; 5.11 up to, but not including, 5.15.212; 5.16 up to, but not including, 6.1.178; 6.2 up to, but not including, 6.6.145; 6.7 up to, but not including, 6.12.96; 6.13 up to, but not including, 6.18.39; 6.19 up to, but not including, 7.1.4; 7.2 | 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.96, 6.18.39 |
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 NVD.
Official description
In the Linux kernel, the following vulnerability has been resolved: USB: ldusb: fix use-after-free on disconnect race mutex_unlock() may access the mutex structure after releasing the lock and therefore cannot be used to manage lifetime of objects directly (unlike spinlocks and refcounts). [1][2] Use a kref to release the driver data to avoid use-after-free in mutex_unlock() when release() races with disconnect(). [1] a51749ab34d9 ("locking/mutex: Document that mutex_unlock() is non-atomic") [2] 2b9d9e0a9ba0 ("locking/mutex: Clarify that mutex_unlock(), and most other sleeping locks, can still use the lock object after it's unlocked")
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: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/02ca08fff74cf9b0a3c4d2cacde1c6edeeb95bb4
- git.kernel.org/stable/c/19bdfc7b3c179331eafa423d87e1336f43bbfeb8
- git.kernel.org/stable/c/2107a4fc8ff1cf1d52f416c1e5cc8e97413a5915
- git.kernel.org/stable/c/a3e794136ab5e3ad1e7019175a4b837aec86db4b
- git.kernel.org/stable/c/af59829e67e11ba2511a9f8e4b9111afc7d1f550
- git.kernel.org/stable/c/d8f69404e1d671326f86d378b9f5bfbd56490e9d
- git.kernel.org/stable/c/e5a9bdce4bfd3e2226b5f3df5fb8385d6935ee69
- git.kernel.org/stable/c/fc55923a972e715f9a27187b47d4920709e23d85
Recent Use After Free vulnerabilities
- 9.8 Critical severity
- 7.8 High severity
- 8.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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