Linux: Use After Free
CVE-2023-52530 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 2408f491ff998d674707725eadc47d8930aced09, e8e599a635066c50ac214c3e10858f1d37e03022, e8a834eb09bb95c2bf9c76f1a28ecef7d8c439d0 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 0.34% 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 2408f491ff998d674707725eadc47d8930aced09 or e8e599a635066c50ac214c3e10858f1d37e03022 or e8a834eb09bb95c2bf9c76f1a28ecef7d8c439d0 or 2f4e16e39e4f5e78248dd9e51276a83203950b36, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.4.285 or 5.10.288 or 5.15.169 or 6.1.57, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | fdf7cb4185b60c68e1a75e61691c4afdc15dea0e up to, but not including, 2408f491ff998d674707725eadc47d8930aced09; fdf7cb4185b60c68e1a75e61691c4afdc15dea0e up to, but not including, e8e599a635066c50ac214c3e10858f1d37e03022; fdf7cb4185b60c68e1a75e61691c4afdc15dea0e up to, but not including, e8a834eb09bb95c2bf9c76f1a28ecef7d8c439d0; fdf7cb4185b60c68e1a75e61691c4afdc15dea0e up to, but not including, 2f4e16e39e4f5e78248dd9e51276a83203950b36; fdf7cb4185b60c68e1a75e61691c4afdc15dea0e up to, but not including, 65c72a7201704574dace708cbc96a8f367b1491d; fdf7cb4185b60c68e1a75e61691c4afdc15dea0e up to, but not including, 31db78a4923ef5e2008f2eed321811ca79e7f71b; ef810e7c3d2a8fb3bbd23726599c487c30ea747e; a0a8a11d1630cd648dc1ce86da620b4e240e0315; and 13 more ranges | 2408f491ff998d674707725eadc47d8930aced09, e8e599a635066c50ac214c3e10858f1d37e03022, e8a834eb09bb95c2bf9c76f1a28ecef7d8c439d0, 2f4e16e39e4f5e78248dd9e51276a83203950b36, 65c72a7201704574dace708cbc96a8f367b1491d, 31db78a4923ef5e2008f2eed321811ca79e7f71b |
| Linux | Linux Kernel | 4.14 up to, but not including, 5.4.285; 5.5 up to, but not including, 5.10.288; 5.11 up to, but not including, 5.15.169; 5.16 up to, but not including, 6.1.57; 6.2 up to, but not including, 6.5.7; 6.6 | 5.4.285, 5.10.288, 5.15.169, 6.1.57, 6.5.7 |
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 | 8.8 | High | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: fix potential key use-after-free When ieee80211_key_link() is called by ieee80211_gtk_rekey_add() but returns 0 due to KRACK protection (identical key reinstall), ieee80211_gtk_rekey_add() will still return a pointer into the key, in a potential use-after-free. This normally doesn't happen since it's only called by iwlwifi in case of WoWLAN rekey offload which has its own KRACK protection, but still better to fix, do that by returning an error code and converting that to success on the cfg80211 boundary only, leaving the error for bad callers of ieee80211_gtk_rekey_add().
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
- git.kernel.org/stable/c/2408f491ff998d674707725eadc47d8930aced09
- git.kernel.org/stable/c/2f4e16e39e4f5e78248dd9e51276a83203950b36
- git.kernel.org/stable/c/31db78a4923ef5e2008f2eed321811ca79e7f71b
- git.kernel.org/stable/c/65c72a7201704574dace708cbc96a8f367b1491d
- git.kernel.org/stable/c/e8a834eb09bb95c2bf9c76f1a28ecef7d8c439d0
- git.kernel.org/stable/c/e8e599a635066c50ac214c3e10858f1d37e03022
Other references
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.0 High severity
- 7.8 High severity
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