Linux: Use After Free
CVE-2024-50086 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 0f62358ce85b2d4c949ef1b648be01b29cec667a, a9839c37fd813b432988f58a9d9dd59253d3eb2c, 5511999e9615e4318e9142d23b29bd1597befc08 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 0.48% 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 0f62358ce85b2d4c949ef1b648be01b29cec667a or a9839c37fd813b432988f58a9d9dd59253d3eb2c or 5511999e9615e4318e9142d23b29bd1597befc08 or ee371898b53a9b9b51c02d22a8c31bfb86d45f0d, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.1.114 or 6.6.58 or 6.11.5, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 0626e6641f6b467447c81dd7678a69c66f7746cf up to, but not including, 0f62358ce85b2d4c949ef1b648be01b29cec667a; 0626e6641f6b467447c81dd7678a69c66f7746cf up to, but not including, a9839c37fd813b432988f58a9d9dd59253d3eb2c; 0626e6641f6b467447c81dd7678a69c66f7746cf up to, but not including, 5511999e9615e4318e9142d23b29bd1597befc08; 0626e6641f6b467447c81dd7678a69c66f7746cf up to, but not including, ee371898b53a9b9b51c02d22a8c31bfb86d45f0d; 0626e6641f6b467447c81dd7678a69c66f7746cf up to, but not including, 7aa8804c0b67b3cb263a472d17f2cb50d7f1a930; 5.15 | 0f62358ce85b2d4c949ef1b648be01b29cec667a, a9839c37fd813b432988f58a9d9dd59253d3eb2c, 5511999e9615e4318e9142d23b29bd1597befc08, ee371898b53a9b9b51c02d22a8c31bfb86d45f0d, 7aa8804c0b67b3cb263a472d17f2cb50d7f1a930 |
| Linux | Linux Kernel | before 6.1.114; 6.2 up to, but not including, 6.6.58; 6.7 up to, but not including, 6.11.5; 6.12 | 6.1.114, 6.6.58, 6.11.5 |
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
- 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 NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 9.8 | Critical | CNA |
| CVSS 3.1 | 7.0 | High | NVD |
| CVSS 3.1 | 7.8 | High | CISA (ADP) |
Official description
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix user-after-free from session log off There is racy issue between smb2 session log off and smb2 session setup. It will cause user-after-free from session log off. This add session_lock when setting SMB2_SESSION_EXPIRED and referece count to session struct not to free session while it is being used.
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
Other references
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 8.8 High severity
- 7.5 High severity
- 7.8 High severity
Spotted an error? Tell us.