Linux: Use After Free
CVE-2023-53572 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 f95ff838ac39f861d1f95a0f3bbb1e01c2517d79, 08cc7cd2c2a29a2abf5bceb8f048c0734d3694ba, 3d90921f91fc6a8c801d527bb5848c99e335c1cf 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 0.14% 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 f95ff838ac39f861d1f95a0f3bbb1e01c2517d79 or 08cc7cd2c2a29a2abf5bceb8f048c0734d3694ba or 3d90921f91fc6a8c801d527bb5848c99e335c1cf or 0a719f0e4b6f233979e219baff73923e76a96e09, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.15.121 or 6.1.39 or 6.3.13 or 6.4.4, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 77d8f3068c63ee0983f0b5ba3207d3f7cce11be4 up to, but not including, f95ff838ac39f861d1f95a0f3bbb1e01c2517d79; 77d8f3068c63ee0983f0b5ba3207d3f7cce11be4 up to, but not including, 08cc7cd2c2a29a2abf5bceb8f048c0734d3694ba; 77d8f3068c63ee0983f0b5ba3207d3f7cce11be4 up to, but not including, 3d90921f91fc6a8c801d527bb5848c99e335c1cf; 77d8f3068c63ee0983f0b5ba3207d3f7cce11be4 up to, but not including, 0a719f0e4b6f233979e219baff73923e76a96e09; 77d8f3068c63ee0983f0b5ba3207d3f7cce11be4 up to, but not including, 632c60ecd25dbacee54d5581fe3aeb834b57010a; 5.11 | f95ff838ac39f861d1f95a0f3bbb1e01c2517d79, 08cc7cd2c2a29a2abf5bceb8f048c0734d3694ba, 3d90921f91fc6a8c801d527bb5848c99e335c1cf, 0a719f0e4b6f233979e219baff73923e76a96e09, 632c60ecd25dbacee54d5581fe3aeb834b57010a |
| Linux | Linux Kernel | 5.11 up to, but not including, 5.15.121; 5.16 up to, but not including, 6.1.39; 6.2 up to, but not including, 6.3.13; 6.4 up to, but not including, 6.4.4 | 5.15.121, 6.1.39, 6.3.13, 6.4.4 |
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 | 7.0 | High | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
In the Linux kernel, the following vulnerability has been resolved: clk: imx: scu: use _safe list iterator to avoid a use after free This loop is freeing "clk" so it needs to use list_for_each_entry_safe(). Otherwise it dereferences a freed variable to get the next item on the loop.
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.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/08cc7cd2c2a29a2abf5bceb8f048c0734d3694ba
- git.kernel.org/stable/c/0a719f0e4b6f233979e219baff73923e76a96e09
- git.kernel.org/stable/c/3d90921f91fc6a8c801d527bb5848c99e335c1cf
- git.kernel.org/stable/c/632c60ecd25dbacee54d5581fe3aeb834b57010a
- git.kernel.org/stable/c/f95ff838ac39f861d1f95a0f3bbb1e01c2517d79
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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