Linux: Use After Free
CVE-2026-63930 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 b71893c57730809c222766e5718bb33610f11963, 2ff615fc455acda5425c4900160cbe11cfea4449, d2759d49860b9a39b5cde2fb88e4b822ddf5f58f 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 0.16% 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 b71893c57730809c222766e5718bb33610f11963 or 2ff615fc455acda5425c4900160cbe11cfea4449 or d2759d49860b9a39b5cde2fb88e4b822ddf5f58f or 29783e6b6ec0b7152a15e53a063f17537e81177d, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.259 or 5.15.210 or 6.1.176 or 6.6.143, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 48b66f8f936f369bb1a43c12aedbfeb2975baf4c up to, but not including, b71893c57730809c222766e5718bb33610f11963; 48b66f8f936f369bb1a43c12aedbfeb2975baf4c up to, but not including, 2ff615fc455acda5425c4900160cbe11cfea4449; 48b66f8f936f369bb1a43c12aedbfeb2975baf4c up to, but not including, d2759d49860b9a39b5cde2fb88e4b822ddf5f58f; 48b66f8f936f369bb1a43c12aedbfeb2975baf4c up to, but not including, 29783e6b6ec0b7152a15e53a063f17537e81177d; 48b66f8f936f369bb1a43c12aedbfeb2975baf4c up to, but not including, e965627f0d442bfcae3f496c90cb653fb0917a61; 48b66f8f936f369bb1a43c12aedbfeb2975baf4c up to, but not including, a3763ae33476328cf8d661742deb9daec78eac96; 48b66f8f936f369bb1a43c12aedbfeb2975baf4c up to, but not including, 9319c94f63ed10723afd738d79f5617daba87cc8; 48b66f8f936f369bb1a43c12aedbfeb2975baf4c up to, but not including, 6f5ed4f2c7c83f33344e0ba179f72a12e5dad4a4; and 1 more ranges | b71893c57730809c222766e5718bb33610f11963, 2ff615fc455acda5425c4900160cbe11cfea4449, d2759d49860b9a39b5cde2fb88e4b822ddf5f58f, 29783e6b6ec0b7152a15e53a063f17537e81177d, e965627f0d442bfcae3f496c90cb653fb0917a61, a3763ae33476328cf8d661742deb9daec78eac96 |
| Linux | Linux Kernel | 4.16 up to, but not including, 5.10.259; 5.11 up to, but not including, 5.15.210; 5.16 up to, but not including, 6.1.176; 6.2 up to, but not including, 6.6.143; 6.7 up to, but not including, 6.12.93; 6.13 up to, but not including, 6.18.35; 6.19 up to, but not including, 7.0.12; 7.1 | 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.93, 6.18.35 |
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: iio: buffer: hw-consumer: fix use-after-free in error path In the err_put_buffers cleanup path of iio_hw_consumer_alloc(), the code was using list_for_each_entry() to iterate through buffers while calling iio_buffer_put() which can free the current buffer if refcount drops to 0. The list_for_each_entry() loop macro then evaluates buf->head.next to continue iteration, accessing the freed buffer. Fix this by using list_for_each_entry_safe().
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.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/29783e6b6ec0b7152a15e53a063f17537e81177d
- git.kernel.org/stable/c/2ff615fc455acda5425c4900160cbe11cfea4449
- git.kernel.org/stable/c/6f5ed4f2c7c83f33344e0ba179f72a12e5dad4a4
- git.kernel.org/stable/c/9319c94f63ed10723afd738d79f5617daba87cc8
- git.kernel.org/stable/c/a3763ae33476328cf8d661742deb9daec78eac96
- git.kernel.org/stable/c/b71893c57730809c222766e5718bb33610f11963
- git.kernel.org/stable/c/d2759d49860b9a39b5cde2fb88e4b822ddf5f58f
- git.kernel.org/stable/c/e965627f0d442bfcae3f496c90cb653fb0917a61
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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