Linux: Use After Free
CVE-2024-38545 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 330c825e66ef65278e4ebe57fd49c1d6f3f4e34e, 763780ef0336a973e933e40e919339381732dcaf, 63da190eeb5c9d849b71f457b15b308c94cbaf08 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 0.25% 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 330c825e66ef65278e4ebe57fd49c1d6f3f4e34e or 763780ef0336a973e933e40e919339381732dcaf or 63da190eeb5c9d849b71f457b15b308c94cbaf08 or 39d26cf46306bdc7ae809ecfdbfeff5aa1098911, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.15.168 or 6.1.93 or 6.6.33 or 6.8.12, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 9a4435375cd151e07c0c38fa601b00115986091b up to, but not including, 330c825e66ef65278e4ebe57fd49c1d6f3f4e34e; 9a4435375cd151e07c0c38fa601b00115986091b up to, but not including, 763780ef0336a973e933e40e919339381732dcaf; 9a4435375cd151e07c0c38fa601b00115986091b up to, but not including, 63da190eeb5c9d849b71f457b15b308c94cbaf08; 9a4435375cd151e07c0c38fa601b00115986091b up to, but not including, 39d26cf46306bdc7ae809ecfdbfeff5aa1098911; 9a4435375cd151e07c0c38fa601b00115986091b up to, but not including, 37a7559dc1358a8d300437e99ed8ecdab0671507; 9a4435375cd151e07c0c38fa601b00115986091b up to, but not including, a942ec2745ca864cd8512142100e4027dc306a42; 4.9 | 330c825e66ef65278e4ebe57fd49c1d6f3f4e34e, 763780ef0336a973e933e40e919339381732dcaf, 63da190eeb5c9d849b71f457b15b308c94cbaf08, 39d26cf46306bdc7ae809ecfdbfeff5aa1098911, 37a7559dc1358a8d300437e99ed8ecdab0671507, a942ec2745ca864cd8512142100e4027dc306a42 |
| Linux | Linux Kernel | 4.9 up to, but not including, 5.15.168; 5.16 up to, but not including, 6.1.93; 6.2 up to, but not including, 6.6.33; 6.7 up to, but not including, 6.8.12; 6.9 up to, but not including, 6.9.3 | 5.15.168, 6.1.93, 6.6.33, 6.8.12, 6.9.3 |
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 | 7.8 | High | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
In the Linux kernel, the following vulnerability has been resolved: RDMA/hns: Fix UAF for cq async event The refcount of CQ is not protected by locks. When CQ asynchronous events and CQ destruction are concurrent, CQ may have been released, which will cause UAF. Use the xa_lock() to protect the CQ refcount.
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
- git.kernel.org/stable/c/330c825e66ef65278e4ebe57fd49c1d6f3f4e34e
- git.kernel.org/stable/c/37a7559dc1358a8d300437e99ed8ecdab0671507
- git.kernel.org/stable/c/39d26cf46306bdc7ae809ecfdbfeff5aa1098911
- git.kernel.org/stable/c/63da190eeb5c9d849b71f457b15b308c94cbaf08
- git.kernel.org/stable/c/763780ef0336a973e933e40e919339381732dcaf
- git.kernel.org/stable/c/a942ec2745ca864cd8512142100e4027dc306a42
Recent Use After Free vulnerabilities
- 7.0 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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