Linux: Use After Free
CVE-2023-53398 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 52e6e7a0bc04c85012a9251c7cf2d444a77eb966, 6afdedc4e66e3846ce497744f01b95c34bf39d21, 3a50cf1e8e5157b82268eee7e330dbe5736a0948 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 52e6e7a0bc04c85012a9251c7cf2d444a77eb966 or 6afdedc4e66e3846ce497744f01b95c34bf39d21 or 3a50cf1e8e5157b82268eee7e330dbe5736a0948, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.1.18 or 6.2.5, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 58a518948f60153e8f6cb8361d2712aa3a1af94a up to, but not including, 52e6e7a0bc04c85012a9251c7cf2d444a77eb966; 58a518948f60153e8f6cb8361d2712aa3a1af94a up to, but not including, 6afdedc4e66e3846ce497744f01b95c34bf39d21; 58a518948f60153e8f6cb8361d2712aa3a1af94a up to, but not including, 3a50cf1e8e5157b82268eee7e330dbe5736a0948; 6.0 | 52e6e7a0bc04c85012a9251c7cf2d444a77eb966, 6afdedc4e66e3846ce497744f01b95c34bf39d21, 3a50cf1e8e5157b82268eee7e330dbe5736a0948 |
| Linux | Linux Kernel | 6.0 up to, but not including, 6.1.18; 6.2 up to, but not including, 6.2.5 | 6.1.18, 6.2.5 |
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 | 7.8 | High | NVD |
| CVSS 3.1 | 7.8 | High | CISA (ADP) |
Official description
In the Linux kernel, the following vulnerability has been resolved: mlx5: fix possible ptp queue fifo use-after-free Fifo indexes are not checked during pop operations and it leads to potential use-after-free when poping from empty queue. Such case was possible during re-sync action. WARN_ON_ONCE covers future cases. There were out-of-order cqe spotted which lead to drain of the queue and use-after-free because of lack of fifo pointers check. Special check and counter are added to avoid resync operation if SKB could not exist in the fifo because of OOO cqe (skb_id must be between consumer and producer index).
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
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