Linux: Use After Free
CVE-2023-53263 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 3f27451c9f29d5ed00232968680c7838a44dcac7, 872feeecd08c81d212a52211d212897b8a857544, 1b254b791d7b7dea6e8adc887fbbd51746d8bb27 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 0.16% 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 3f27451c9f29d5ed00232968680c7838a44dcac7 or 872feeecd08c81d212a52211d212897b8a857544 or 1b254b791d7b7dea6e8adc887fbbd51746d8bb27, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.1.47 or 6.4.12, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 95983aea80038539ebc70e41e73e9bb4eabd1a92 up to, but not including, 3f27451c9f29d5ed00232968680c7838a44dcac7; 95983aea80038539ebc70e41e73e9bb4eabd1a92 up to, but not including, 872feeecd08c81d212a52211d212897b8a857544; 95983aea80038539ebc70e41e73e9bb4eabd1a92 up to, but not including, 1b254b791d7b7dea6e8adc887fbbd51746d8bb27; 6.0 | 3f27451c9f29d5ed00232968680c7838a44dcac7, 872feeecd08c81d212a52211d212897b8a857544, 1b254b791d7b7dea6e8adc887fbbd51746d8bb27 |
| Linux | Linux Kernel | 6.0 up to, but not including, 6.1.47; 6.2 up to, but not including, 6.4.12; 6.5 | 6.1.47, 6.4.12 |
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: drm/nouveau/disp: fix use-after-free in error handling of nouveau_connector_create We can't simply free the connector after calling drm_connector_init on it. We need to clean up the drm side first. It might not fix all regressions from commit 2b5d1c29f6c4 ("drm/nouveau/disp: PIOR DP uses GPIO for HPD, not PMGR AUX interrupts"), but at least it fixes a memory corruption in error handling related to that commit.
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
- 7.0 High severity
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