Linux: Use After Free
CVE-2026-64266 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 1f9156714592356b4fda57beac7eab9c2a462dd3, 5630da218a45ba80f0aba0846cbe8aa655da122b, 1ca605cfa59377f0143fb35b5b01360f37d1b7c4 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 1f9156714592356b4fda57beac7eab9c2a462dd3 or 5630da218a45ba80f0aba0846cbe8aa655da122b or 1ca605cfa59377f0143fb35b5b01360f37d1b7c4 or 0e4a5a000123d81234e27a2f8187688cf608f755, 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 | c3021629a0d820247ee12b6c5192a1d5380e21c6 up to, but not including, 1f9156714592356b4fda57beac7eab9c2a462dd3; c3021629a0d820247ee12b6c5192a1d5380e21c6 up to, but not including, 5630da218a45ba80f0aba0846cbe8aa655da122b; c3021629a0d820247ee12b6c5192a1d5380e21c6 up to, but not including, 1ca605cfa59377f0143fb35b5b01360f37d1b7c4; c3021629a0d820247ee12b6c5192a1d5380e21c6 up to, but not including, 0e4a5a000123d81234e27a2f8187688cf608f755; c3021629a0d820247ee12b6c5192a1d5380e21c6 up to, but not including, e6aa539720c3d8def69683ed0c07cf9faea4e8be; c3021629a0d820247ee12b6c5192a1d5380e21c6 up to, but not including, be353caffa8640f5e25fb3714ce8b0cef5e410e5; c3021629a0d820247ee12b6c5192a1d5380e21c6 up to, but not including, 65a1c2551f7e16085acbb54aedde1feaa559ba7a; c3021629a0d820247ee12b6c5192a1d5380e21c6 up to, but not including, b5befa80fdbe287a98480effed9564712924add5; and 1 more ranges | 1f9156714592356b4fda57beac7eab9c2a462dd3, 5630da218a45ba80f0aba0846cbe8aa655da122b, 1ca605cfa59377f0143fb35b5b01360f37d1b7c4, 0e4a5a000123d81234e27a2f8187688cf608f755, e6aa539720c3d8def69683ed0c07cf9faea4e8be, be353caffa8640f5e25fb3714ce8b0cef5e410e5 |
| Linux | Linux Kernel | 2.6.35 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 | 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 CNA.
Official description
In the Linux kernel, the following vulnerability has been resolved: fuse: re-lock request before returning from fuse_ref_folio() fuse_ref_folio() unlocks the request but does not re-lock it before returning. fuse_chan_abort() can end the request and the async end callback (eg fuse_writepage_free()) can free the args while the subsequent copy chain logic after fuse_ref_folio() accesses them, leading to use-after-free issues. Fix this by locking the request in fuse_ref_folio() before returning.
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/0e4a5a000123d81234e27a2f8187688cf608f755
- git.kernel.org/stable/c/1ca605cfa59377f0143fb35b5b01360f37d1b7c4
- git.kernel.org/stable/c/1f9156714592356b4fda57beac7eab9c2a462dd3
- git.kernel.org/stable/c/5630da218a45ba80f0aba0846cbe8aa655da122b
- git.kernel.org/stable/c/65a1c2551f7e16085acbb54aedde1feaa559ba7a
- git.kernel.org/stable/c/b5befa80fdbe287a98480effed9564712924add5
- git.kernel.org/stable/c/be353caffa8640f5e25fb3714ce8b0cef5e410e5
- git.kernel.org/stable/c/e6aa539720c3d8def69683ed0c07cf9faea4e8be
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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