Linux: Use After Free
CVE-2026-53381 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 607a1d4c42f649e6197567c0448fd9ebb316cd42, 1cc0e3a0c6499aaaa2f21a4fcbba388486afb25e, 0b809199ff87c44487e516a725dd4be2185712ce 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 0.14% 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 607a1d4c42f649e6197567c0448fd9ebb316cd42 or 1cc0e3a0c6499aaaa2f21a4fcbba388486afb25e or 0b809199ff87c44487e516a725dd4be2185712ce or 2181a09ba980f142650fb053666350ead4471cfe, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.260 or 5.15.211 or 6.1.177 or 6.6.144, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 548e1f2bac1d4df91a6138f26bb4ab00323fd948 up to, but not including, 607a1d4c42f649e6197567c0448fd9ebb316cd42; cfd1aa3e2b71f3327cb373c45a897c9028c62b35 up to, but not including, 1cc0e3a0c6499aaaa2f21a4fcbba388486afb25e; 83b375c6efef69b1066ad2d79601221e7892745a up to, but not including, 0b809199ff87c44487e516a725dd4be2185712ce; bfd17b6138df0122a95989457d8e18ce0b86165e up to, but not including, 2181a09ba980f142650fb053666350ead4471cfe; b26923512dbe57ae4917bafd31396d22a9d1691a up to, but not including, 97c4691653d145dcc699eca5d3aba3219a520f1f; 26e5c67deb2e1f42a951f022fdf5b9f7eb747b01 up to, but not including, 2abfd3ffbd9452f72535d96ff3982b3ab1f8f2f9; 26e5c67deb2e1f42a951f022fdf5b9f7eb747b01 up to, but not including, 39a2b95e008665c14f84e50ed411d898df7cd11b; 26e5c67deb2e1f42a951f022fdf5b9f7eb747b01 up to, but not including, e09412a714bcd49375198427bb4aa005037a9d6f; and 9 more ranges | 607a1d4c42f649e6197567c0448fd9ebb316cd42, 1cc0e3a0c6499aaaa2f21a4fcbba388486afb25e, 0b809199ff87c44487e516a725dd4be2185712ce, 2181a09ba980f142650fb053666350ead4471cfe, 97c4691653d145dcc699eca5d3aba3219a520f1f, 2abfd3ffbd9452f72535d96ff3982b3ab1f8f2f9 |
| Linux | Linux Kernel | 5.10.246 up to, but not including, 5.10.260; 5.15.196 up to, but not including, 5.15.211; 6.1.158 up to, but not including, 6.1.177; 6.6.115 up to, but not including, 6.6.144; 6.12.54 up to, but not including, 6.12.95; 6.17.4 up to, but not including, 6.18.37; 6.19 up to, but not including, 7.0.14; 7.1 up to, but not including, 7.1.2 | 5.10.260, 5.15.211, 6.1.177, 6.6.144, 6.12.95, 6.18.37 |
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: virtiofs: fix UAF on submount umount iput() called from fuse_release_end() can Oops if the super block has already been destroyed. Normally this is prevented by waiting for num_waiting to go down to zero before commencing with super block shutdown. This only works, however, for the last submount instance, as the wait counter is per connection, not per superblock. Revert to using synchronous release requests for the auto_submounts case, which is virtiofs only at this time.
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
- git.kernel.org/stable/c/06b41351779e9289e8785694ade9042ae85e41ea
- git.kernel.org/stable/c/0b809199ff87c44487e516a725dd4be2185712ce
- git.kernel.org/stable/c/1cc0e3a0c6499aaaa2f21a4fcbba388486afb25e
- git.kernel.org/stable/c/2181a09ba980f142650fb053666350ead4471cfe
- git.kernel.org/stable/c/2abfd3ffbd9452f72535d96ff3982b3ab1f8f2f9
- git.kernel.org/stable/c/39a2b95e008665c14f84e50ed411d898df7cd11b
- git.kernel.org/stable/c/607a1d4c42f649e6197567c0448fd9ebb316cd42
- git.kernel.org/stable/c/97c4691653d145dcc699eca5d3aba3219a520f1f
- git.kernel.org/stable/c/e09412a714bcd49375198427bb4aa005037a9d6f
Recent Use After Free vulnerabilities
- 8.8 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 7.8 High severity
- 9.8 Critical severity
- 8.8 High severity
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