Linux: Use After Free
CVE-2026-46154 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 7.0 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 ce9aaa3af445c391735c9d000c4db60dfd5640d4, 0f54f6355575971673d8aac7da107ec4178e45bd, 80afd4c84bc8f5e80145ce35279f5ce53f6043db 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 0.12% 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 ce9aaa3af445c391735c9d000c4db60dfd5640d4 or 0f54f6355575971673d8aac7da107ec4178e45bd or 80afd4c84bc8f5e80145ce35279f5ce53f6043db, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.18.32 or 7.0.7, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | a5bd6ba30b3364354269b81ac55c2edca9a96d6d up to, but not including, ce9aaa3af445c391735c9d000c4db60dfd5640d4; a5bd6ba30b3364354269b81ac55c2edca9a96d6d up to, but not including, 0f54f6355575971673d8aac7da107ec4178e45bd; a5bd6ba30b3364354269b81ac55c2edca9a96d6d up to, but not including, 80afd4c84bc8f5e80145ce35279f5ce53f6043db; 6.18 | ce9aaa3af445c391735c9d000c4db60dfd5640d4, 0f54f6355575971673d8aac7da107ec4178e45bd, 80afd4c84bc8f5e80145ce35279f5ce53f6043db |
| Linux | Linux Kernel | 6.18 up to, but not including, 6.18.32; 6.19 up to, but not including, 7.0.7; 7.1 | 6.18.32, 7.0.7 |
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
- HighSuccess depends on conditions outside the attacker's control.
- 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:H/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: sched_ext: Read scx_root under scx_cgroup_ops_rwsem in cgroup setters scx_group_set_{weight,idle,bandwidth}() cache scx_root before acquiring scx_cgroup_ops_rwsem, so the pointer can be stale by the time the op runs. If the loaded scheduler is disabled and freed (via RCU work) and another is enabled between the naked load and the rwsem acquire, the reader sees scx_cgroup_enabled=true (the new scheduler's) but dereferences the freed one - UAF on SCX_HAS_OP(sch, ...) / SCX_CALL_OP(sch, ...). scx_cgroup_enabled is toggled only under scx_cgroup_ops_rwsem write (scx_cgroup_{init,exit}), so reading scx_root inside the rwsem read section correlates @sch with the enabled snapshot.
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
Recent Use After Free vulnerabilities
- 8.3 High severity
- 8.8 High severity
- 8.3 High severity
- 8.3 High severity
- 8.8 High severity
- 7.5 High severity
Spotted an error? Tell us.