Linux: Use After Free
CVE-2024-35863 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 494c91e1e9413b407d12166a61b84200d4d54fac, 0a15ba88a32fa7a516aff7ffd27befed5334dff2, 16d58c6a7db5050b9638669084b63fc05f951825 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 0.66% chance of exploitation within 30 days, higher than 52% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 494c91e1e9413b407d12166a61b84200d4d54fac or 0a15ba88a32fa7a516aff7ffd27befed5334dff2 or 16d58c6a7db5050b9638669084b63fc05f951825 or 69ccf040acddf33a3a85ec0f6b45ef84b0f7ec29, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.1.85 or 6.6.26 or 6.8.5, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 7f48558e6489d032b1584b0cc9ac4bb11072c034 up to, but not including, 494c91e1e9413b407d12166a61b84200d4d54fac; 7f48558e6489d032b1584b0cc9ac4bb11072c034 up to, but not including, 0a15ba88a32fa7a516aff7ffd27befed5334dff2; 7f48558e6489d032b1584b0cc9ac4bb11072c034 up to, but not including, 16d58c6a7db5050b9638669084b63fc05f951825; 7f48558e6489d032b1584b0cc9ac4bb11072c034 up to, but not including, 69ccf040acddf33a3a85ec0f6b45ef84b0f7ec29; a67172a013953664b1dad03c648200c70b90506c; 3.12.48 up to, but not including, 3.13; 3.13 | 494c91e1e9413b407d12166a61b84200d4d54fac, 0a15ba88a32fa7a516aff7ffd27befed5334dff2, 16d58c6a7db5050b9638669084b63fc05f951825, 69ccf040acddf33a3a85ec0f6b45ef84b0f7ec29, 3.13 |
| Linux | Linux Kernel | 6.0 up to, but not including, 6.1.85; 6.2 up to, but not including, 6.6.26; 6.7 up to, but not including, 6.8.5; 6.9 | 6.1.85, 6.6.26, 6.8.5 |
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: smb: client: fix potential UAF in is_valid_oplock_break() Skip sessions that are being teared down (status == SES_EXITING) to avoid UAF.
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: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 7.8 High severity
Spotted an error? Tell us.