Linux: Use After Free
CVE-2023-53377 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 4fe07d55a5461e66a55fbefb57f85ff0facea32b, b6353518ef8180816e863aa23b06456f395404d6, d017880782cf71f8820ee4a2002843893176501d 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 0.15% 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 4fe07d55a5461e66a55fbefb57f85ff0facea32b or b6353518ef8180816e863aa23b06456f395404d6 or d017880782cf71f8820ee4a2002843893176501d or 33f736187d08f6bc822117629f263b97d3df4165, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.1.39 or 6.3.13 or 6.4.4, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 76894f3e2f71177747b8b4763fb180e800279585 up to, but not including, 4fe07d55a5461e66a55fbefb57f85ff0facea32b; 76894f3e2f71177747b8b4763fb180e800279585 up to, but not including, b6353518ef8180816e863aa23b06456f395404d6; 76894f3e2f71177747b8b4763fb180e800279585 up to, but not including, d017880782cf71f8820ee4a2002843893176501d; 76894f3e2f71177747b8b4763fb180e800279585 up to, but not including, 33f736187d08f6bc822117629f263b97d3df4165; 2d046892a493d9760c35fdaefc3017f27f91b621; 6.0.16 up to, but not including, 6.1; 6.1 | 4fe07d55a5461e66a55fbefb57f85ff0facea32b, b6353518ef8180816e863aa23b06456f395404d6, d017880782cf71f8820ee4a2002843893176501d, 33f736187d08f6bc822117629f263b97d3df4165, 6.1 |
| Linux | Linux Kernel | 6.0.16 up to, but not including, 6.1.39; 6.2 up to, but not including, 6.3.13; 6.4 up to, but not including, 6.4.4 | 6.1.39, 6.3.13, 6.4.4 |
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 | NVD |
| CVSS 3.1 | 7.8 | High | CISA (ADP) |
Official description
In the Linux kernel, the following vulnerability has been resolved: cifs: prevent use-after-free by freeing the cfile later In smb2_compound_op we have a possible use-after-free which can cause hard to debug problems later on. This was revealed during stress testing with KASAN enabled kernel. Fixing it by moving the cfile free call to a few lines below, after the usage.
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
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
Spotted an error? Tell us.