Linux: Use After Free
CVE-2025-68817 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 446beed646b2e426dd53d27358365f8678e1dd01, d092de8a26c952379ded8e6b0bda31d89befac1a, d64977495e44855f2b28d8ce56107c963a7a50e4 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 0.44% 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 446beed646b2e426dd53d27358365f8678e1dd01 or d092de8a26c952379ded8e6b0bda31d89befac1a or d64977495e44855f2b28d8ce56107c963a7a50e4 or 21a3d01fc6db5129f81edb0ab7cb94fd758bcbea, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.15.199 or 6.1.160 or 6.6.120 or 6.12.64, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | dd45db4d9bbc8f122a9b4db5ce94ae29fcf03d3c up to, but not including, 446beed646b2e426dd53d27358365f8678e1dd01; 7b58ee8d0b91359554cf219cd4f33872ea2afd66 up to, but not including, d092de8a26c952379ded8e6b0bda31d89befac1a; 33b235a6e6ebe0f05f3586a71e8d281d00f71e2e up to, but not including, d64977495e44855f2b28d8ce56107c963a7a50e4; 33b235a6e6ebe0f05f3586a71e8d281d00f71e2e up to, but not including, 21a3d01fc6db5129f81edb0ab7cb94fd758bcbea; 33b235a6e6ebe0f05f3586a71e8d281d00f71e2e up to, but not including, 063cbbc6f595ea36ad146e1b7d2af820894beb21; 33b235a6e6ebe0f05f3586a71e8d281d00f71e2e up to, but not including, b39a1833cc4a2755b02603eec3a71a85e9dff926; 5.15.145 up to, but not including, 5.15.199; 6.1.71 up to, but not including, 6.1.160; and 1 more ranges | 446beed646b2e426dd53d27358365f8678e1dd01, d092de8a26c952379ded8e6b0bda31d89befac1a, d64977495e44855f2b28d8ce56107c963a7a50e4, 21a3d01fc6db5129f81edb0ab7cb94fd758bcbea, 063cbbc6f595ea36ad146e1b7d2af820894beb21, b39a1833cc4a2755b02603eec3a71a85e9dff926 |
| Linux | Linux Kernel | 5.15.145 up to, but not including, 5.15.199; 6.1.71 up to, but not including, 6.1.160; 6.6.1 up to, but not including, 6.6.120; 6.7 up to, but not including, 6.12.64; 6.13 up to, but not including, 6.18.3; 6.6 | 5.15.199, 6.1.160, 6.6.120, 6.12.64, 6.18.3 |
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 | 9.8 | Critical | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free in ksmbd_tree_connect_put under concurrency Under high concurrency, A tree-connection object (tcon) is freed on a disconnect path while another path still holds a reference and later executes *_put()/write on it.
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/063cbbc6f595ea36ad146e1b7d2af820894beb21
- git.kernel.org/stable/c/21a3d01fc6db5129f81edb0ab7cb94fd758bcbea
- git.kernel.org/stable/c/446beed646b2e426dd53d27358365f8678e1dd01
- git.kernel.org/stable/c/b39a1833cc4a2755b02603eec3a71a85e9dff926
- git.kernel.org/stable/c/d092de8a26c952379ded8e6b0bda31d89befac1a
- git.kernel.org/stable/c/d64977495e44855f2b28d8ce56107c963a7a50e4
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 8.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
Spotted an error? Tell us.