Linux: Use After Free
CVE-2023-52776 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited from the same local network by an unauthenticated attacker, without any action from a user. The record lists versions 774de37c147fea81f2c2e4be5082304f4f71d535, d7a5f7f76568e48869916d769e28b9f3ca70c78e, 69bd216e049349886405b1c87a55dce3d35d1ba7 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 0.86% chance of exploitation within 30 days, higher than 59% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 774de37c147fea81f2c2e4be5082304f4f71d535 or d7a5f7f76568e48869916d769e28b9f3ca70c78e or 69bd216e049349886405b1c87a55dce3d35d1ba7, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.5.13 or 6.6.3, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | d889913205cf7ebda905b1e62c5867ed4e39f6c2 up to, but not including, 774de37c147fea81f2c2e4be5082304f4f71d535; d889913205cf7ebda905b1e62c5867ed4e39f6c2 up to, but not including, d7a5f7f76568e48869916d769e28b9f3ca70c78e; d889913205cf7ebda905b1e62c5867ed4e39f6c2 up to, but not including, 69bd216e049349886405b1c87a55dce3d35d1ba7; 6.3 | 774de37c147fea81f2c2e4be5082304f4f71d535, d7a5f7f76568e48869916d769e28b9f3ca70c78e, 69bd216e049349886405b1c87a55dce3d35d1ba7 |
| Linux | Linux Kernel | 6.3 up to, but not including, 6.5.13; 6.6 up to, but not including, 6.6.3 | 6.5.13, 6.6.3 |
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
- AdjacentThe attacker must be on the same local network segment.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- 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:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.8 | High | CNA |
| CVSS 3.1 | 5.9 | Medium | CISA (ADP) |
Official description
In the Linux kernel, the following vulnerability has been resolved: wifi: ath12k: fix dfs-radar and temperature event locking The ath12k active pdevs are protected by RCU but the DFS-radar and temperature event handling code calling ath12k_mac_get_ar_by_pdev_id() was not marked as a read-side critical section. Mark the code in question as RCU read-side critical sections to avoid any potential use-after-free issues. Note that the temperature event handler looks like a place holder currently but would still trigger an RCU lockdep splat. Compile tested only.
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
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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