Linux: Use After Free
CVE-2023-52983 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 7f77f3dab5066a7c9da73d72d1eee895ff84a8d5, 511c922c5bf6c8a166bea826e702336bc2424140, cb1876fc33af26d00efdd473311f1b664c77c44e 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 0.28% 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 7f77f3dab5066a7c9da73d72d1eee895ff84a8d5 or 511c922c5bf6c8a166bea826e702336bc2424140 or cb1876fc33af26d00efdd473311f1b664c77c44e or b600de2d7d3a16f9007fad1bdae82a3951a26af2, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.15.93 or 6.1.11, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 5533742c7cb1bc9b1f0bf401cc397d44a3a9e07a up to, but not including, 7f77f3dab5066a7c9da73d72d1eee895ff84a8d5; 094f3d9314d67691cb21ba091c1b528f6e3c4893 up to, but not including, 511c922c5bf6c8a166bea826e702336bc2424140; 761564d93c8265f65543acf0a576b32d66bfa26a up to, but not including, cb1876fc33af26d00efdd473311f1b664c77c44e; 64dc8c732f5c2b406cc752e6aaa1bd5471159cab up to, but not including, b600de2d7d3a16f9007fad1bdae82a3951a26af2; b22fd72bfebda3956efc4431b60ddfc0a51e03e0; 6.0.16 up to, but not including, 6.1; 5.15.86 up to, but not including, 5.15.93; 6.1.2 up to, but not including, 6.1.11 | 7f77f3dab5066a7c9da73d72d1eee895ff84a8d5, 511c922c5bf6c8a166bea826e702336bc2424140, cb1876fc33af26d00efdd473311f1b664c77c44e, b600de2d7d3a16f9007fad1bdae82a3951a26af2, 6.1, 5.15.93 |
| Linux | Linux Kernel | 5.15.86 up to, but not including, 5.15.93; 6.1.2 up to, but not including, 6.1.11; 6.0.16 | 5.15.93, 6.1.11 |
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 CISA (ADP).
Official description
In the Linux kernel, the following vulnerability has been resolved: block, bfq: fix uaf for bfqq in bic_set_bfqq() After commit 64dc8c732f5c ("block, bfq: fix possible uaf for 'bfqq->bic'"), bic->bfqq will be accessed in bic_set_bfqq(), however, in some context bic->bfqq will be freed, and bic_set_bfqq() is called with the freed bic->bfqq. Fix the problem by always freeing bfqq after bic_set_bfqq().
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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