Linux: Use After Free
CVE-2026-68153 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 ac78549d186090ee7125d28c3a8c376573b36194, 463a264e9094384112a5c8b46f0a9ddaf8566904, fe46b7e06f14f6f94766832df309b249cb689d27 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 ac78549d186090ee7125d28c3a8c376573b36194 or 463a264e9094384112a5c8b46f0a9ddaf8566904 or fe46b7e06f14f6f94766832df309b249cb689d27 or fc1010e7e0204ece6cc0f9af4f473e9553535eab, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 76aa844d5b2fb8c839180d3f5874e333b297e5fd up to, but not including, ac78549d186090ee7125d28c3a8c376573b36194; 76aa844d5b2fb8c839180d3f5874e333b297e5fd up to, but not including, 463a264e9094384112a5c8b46f0a9ddaf8566904; 76aa844d5b2fb8c839180d3f5874e333b297e5fd up to, but not including, fe46b7e06f14f6f94766832df309b249cb689d27; 76aa844d5b2fb8c839180d3f5874e333b297e5fd up to, but not including, fc1010e7e0204ece6cc0f9af4f473e9553535eab; 76aa844d5b2fb8c839180d3f5874e333b297e5fd up to, but not including, d3dc8889d39a676bf840132bd5c5c48cb0daba23; 76aa844d5b2fb8c839180d3f5874e333b297e5fd up to, but not including, 8f5a3abc54ba24dbceb14cc3a719908c4f688091; 76aa844d5b2fb8c839180d3f5874e333b297e5fd up to, but not including, b9fedda2f628e030384228de0dafc574b7fb0c2f; 76aa844d5b2fb8c839180d3f5874e333b297e5fd up to, but not including, e4c804726c4afce3ba648b982d564f6af2cfa328; and 1 more ranges | ac78549d186090ee7125d28c3a8c376573b36194, 463a264e9094384112a5c8b46f0a9ddaf8566904, fe46b7e06f14f6f94766832df309b249cb689d27, fc1010e7e0204ece6cc0f9af4f473e9553535eab, d3dc8889d39a676bf840132bd5c5c48cb0daba23, 8f5a3abc54ba24dbceb14cc3a719908c4f688091 |
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: libceph: remove debugfs files before client teardown ceph_destroy_client() tears down the monitor client before removing the per-client debugfs files. A concurrent read of the monmap debugfs file can enter monmap_show() after ceph_monc_stop() has freed monc->monmap, triggering a use-after-free. Remove the debugfs files before stopping the OSD and monitor clients. debugfs_remove() drains active handlers and prevents new accesses, so the debugfs callbacks can no longer race the rest of client teardown.
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
Other references
- git.kernel.org/stable/c/463a264e9094384112a5c8b46f0a9ddaf8566904
- git.kernel.org/stable/c/8f5a3abc54ba24dbceb14cc3a719908c4f688091
- git.kernel.org/stable/c/ac78549d186090ee7125d28c3a8c376573b36194
- git.kernel.org/stable/c/b9fedda2f628e030384228de0dafc574b7fb0c2f
- git.kernel.org/stable/c/d3dc8889d39a676bf840132bd5c5c48cb0daba23
- git.kernel.org/stable/c/e4c804726c4afce3ba648b982d564f6af2cfa328
- git.kernel.org/stable/c/fc1010e7e0204ece6cc0f9af4f473e9553535eab
- git.kernel.org/stable/c/fe46b7e06f14f6f94766832df309b249cb689d27
Recent Use After Free vulnerabilities
- 7.8 High severity
- 9.8 Critical severity
- 7.5 High severity
- 8.8 High severity
- 7.8 High severity
- 7.8 High severity
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