Linux: Use After Free
CVE-2026-23412 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 d016c216bc75c45128160593a77b864a04dbe7c0, cb2bf5efdb02a2a59faf603604a1066e8266f349, c25e0dec366ae99b7264324ce3c7cbaea34691f9 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 d016c216bc75c45128160593a77b864a04dbe7c0 or cb2bf5efdb02a2a59faf603604a1066e8266f349 or c25e0dec366ae99b7264324ce3c7cbaea34691f9 or 54244d54a971c26a0cd0a9073460ff71f3c51b32, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.6.130 or 6.12.78 or 6.18.20 or 6.19.10, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 84601d6ee68ae820dec97450934797046d62db4b up to, but not including, d016c216bc75c45128160593a77b864a04dbe7c0; 84601d6ee68ae820dec97450934797046d62db4b up to, but not including, cb2bf5efdb02a2a59faf603604a1066e8266f349; 84601d6ee68ae820dec97450934797046d62db4b up to, but not including, c25e0dec366ae99b7264324ce3c7cbaea34691f9; 84601d6ee68ae820dec97450934797046d62db4b up to, but not including, 54244d54a971c26a0cd0a9073460ff71f3c51b32; 84601d6ee68ae820dec97450934797046d62db4b up to, but not including, 24f90fa3994b992d1a09003a3db2599330a5232a; 6.4 | d016c216bc75c45128160593a77b864a04dbe7c0, cb2bf5efdb02a2a59faf603604a1066e8266f349, c25e0dec366ae99b7264324ce3c7cbaea34691f9, 54244d54a971c26a0cd0a9073460ff71f3c51b32, 24f90fa3994b992d1a09003a3db2599330a5232a |
| Linux | Linux Kernel | 6.4.1 up to, but not including, 6.6.130; 6.7 up to, but not including, 6.12.78; 6.13 up to, but not including, 6.18.20; 6.19 up to, but not including, 6.19.10; 6.4; 7.0 | 6.6.130, 6.12.78, 6.18.20, 6.19.10 |
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.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.8 | High | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
In the Linux kernel, the following vulnerability has been resolved: netfilter: bpf: defer hook memory release until rcu readers are done Yiming Qian reports UaF when concurrent process is dumping hooks via nfnetlink_hooks: BUG: KASAN: slab-use-after-free in nfnl_hook_dump_one.isra.0+0xe71/0x10f0 Read of size 8 at addr ffff888003edbf88 by task poc/79 Call Trace: <TASK> nfnl_hook_dump_one.isra.0+0xe71/0x10f0 netlink_dump+0x554/0x12b0 nfnl_hook_get+0x176/0x230 [..] Defer release until after concurrent readers have completed.
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/24f90fa3994b992d1a09003a3db2599330a5232a
- git.kernel.org/stable/c/54244d54a971c26a0cd0a9073460ff71f3c51b32
- git.kernel.org/stable/c/c25e0dec366ae99b7264324ce3c7cbaea34691f9
- git.kernel.org/stable/c/cb2bf5efdb02a2a59faf603604a1066e8266f349
- git.kernel.org/stable/c/d016c216bc75c45128160593a77b864a04dbe7c0
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 9.6 Critical severity
- 9.6 Critical severity
- 9.6 Critical severity
- 8.8 High severity
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