Linux: Use After Free
CVE-2026-64340 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 11d069f85851997b4ea0adf242ed9672dc749b8f, b4222c05066b252b451f9c8c4730b5b60824ea66, 6462de75d2e370c7e74dcfb7b4ae79eb5a6a55ee 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 11d069f85851997b4ea0adf242ed9672dc749b8f or b4222c05066b252b451f9c8c4730b5b60824ea66 or 6462de75d2e370c7e74dcfb7b4ae79eb5a6a55ee or 0b57e5ddbd89df3bc367463de3d2ca66f99a1a5e, 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 | 18bcbcfe9ca2308ebffb40068b51803da9315d97 up to, but not including, 11d069f85851997b4ea0adf242ed9672dc749b8f; 18bcbcfe9ca2308ebffb40068b51803da9315d97 up to, but not including, b4222c05066b252b451f9c8c4730b5b60824ea66; 18bcbcfe9ca2308ebffb40068b51803da9315d97 up to, but not including, 6462de75d2e370c7e74dcfb7b4ae79eb5a6a55ee; 18bcbcfe9ca2308ebffb40068b51803da9315d97 up to, but not including, 0b57e5ddbd89df3bc367463de3d2ca66f99a1a5e; 18bcbcfe9ca2308ebffb40068b51803da9315d97 up to, but not including, ab2bfd7bec4f134b377ec42f513e90c35db94160; 18bcbcfe9ca2308ebffb40068b51803da9315d97 up to, but not including, 766738ecf2b819e54d38763c8d1c8ae6cff14b39; 18bcbcfe9ca2308ebffb40068b51803da9315d97 up to, but not including, 9ba62966461a8e3cc593b62c56ec62eb2d80436d; 18bcbcfe9ca2308ebffb40068b51803da9315d97 up to, but not including, 62fc8eb1b1481051f7bab4aa93d79809053dd09f; and 1 more ranges | 11d069f85851997b4ea0adf242ed9672dc749b8f, b4222c05066b252b451f9c8c4730b5b60824ea66, 6462de75d2e370c7e74dcfb7b4ae79eb5a6a55ee, 0b57e5ddbd89df3bc367463de3d2ca66f99a1a5e, ab2bfd7bec4f134b377ec42f513e90c35db94160, 766738ecf2b819e54d38763c8d1c8ae6cff14b39 |
| Linux | Linux Kernel | 2.6.25 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: legousbtower: 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/0b57e5ddbd89df3bc367463de3d2ca66f99a1a5e
- git.kernel.org/stable/c/11d069f85851997b4ea0adf242ed9672dc749b8f
- git.kernel.org/stable/c/62fc8eb1b1481051f7bab4aa93d79809053dd09f
- git.kernel.org/stable/c/6462de75d2e370c7e74dcfb7b4ae79eb5a6a55ee
- git.kernel.org/stable/c/766738ecf2b819e54d38763c8d1c8ae6cff14b39
- git.kernel.org/stable/c/9ba62966461a8e3cc593b62c56ec62eb2d80436d
- git.kernel.org/stable/c/ab2bfd7bec4f134b377ec42f513e90c35db94160
- git.kernel.org/stable/c/b4222c05066b252b451f9c8c4730b5b60824ea66
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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