Linux: Use After Free
CVE-2023-52760 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 08a28272faa750d4357ea2cb48d2baefd778ea81, bdcb8aa434c6d36b5c215d02a9ef07551be25a37 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 0.26% 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 08a28272faa750d4357ea2cb48d2baefd778ea81 or bdcb8aa434c6d36b5c215d02a9ef07551be25a37, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.1.97 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 | f66af88e33212b57ea86da2c5d66c0d9d5c46344 up to, but not including, 08a28272faa750d4357ea2cb48d2baefd778ea81; f66af88e33212b57ea86da2c5d66c0d9d5c46344 up to, but not including, bdcb8aa434c6d36b5c215d02a9ef07551be25a37; 6.6 | 08a28272faa750d4357ea2cb48d2baefd778ea81, bdcb8aa434c6d36b5c215d02a9ef07551be25a37 |
| Linux | Linux Kernel | before 6.1.97; 6.2 up to, but not including, 6.6.3 | 6.1.97, 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
- 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: gfs2: Fix slab-use-after-free in gfs2_qd_dealloc In gfs2_put_super(), whether withdrawn or not, the quota should be cleaned up by gfs2_quota_cleanup(). Otherwise, struct gfs2_sbd will be freed before gfs2_qd_dealloc (rcu callback) has run for all gfs2_quota_data objects, resulting in use-after-free. Also, gfs2_destroy_threads() and gfs2_quota_cleanup() is already called by gfs2_make_fs_ro(), so in gfs2_put_super(), after calling gfs2_make_fs_ro(), there is no need to call them again.
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
Other references
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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