Linux: Use After Free
CVE-2023-52840 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 2f236d8638f5b43e0c72919a6a27fe286c32053f, 50d12253666195a14c6cd2b81c376e2dbeedbdff, 6c71e065befb2fae8f1461559b940c04e1071bd5 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 0.24% 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 2f236d8638f5b43e0c72919a6a27fe286c32053f or 50d12253666195a14c6cd2b81c376e2dbeedbdff or 6c71e065befb2fae8f1461559b940c04e1071bd5 or 303766bb92c5c225cf40f9bbbe7e29749406e2f2, whichever matches your release line, or a later version.
- Update Linux Kernel to 4.19.299 or 5.4.261 or 5.10.201 or 5.15.139, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 24d28e4f1271cb2f91613dada8f2acccd00eff56 up to, but not including, 2f236d8638f5b43e0c72919a6a27fe286c32053f; 24d28e4f1271cb2f91613dada8f2acccd00eff56 up to, but not including, 50d12253666195a14c6cd2b81c376e2dbeedbdff; 24d28e4f1271cb2f91613dada8f2acccd00eff56 up to, but not including, 6c71e065befb2fae8f1461559b940c04e1071bd5; 24d28e4f1271cb2f91613dada8f2acccd00eff56 up to, but not including, 303766bb92c5c225cf40f9bbbe7e29749406e2f2; 24d28e4f1271cb2f91613dada8f2acccd00eff56 up to, but not including, 7082b1fb5321037bc11ba1cf2d7ed23c6b2b521f; 24d28e4f1271cb2f91613dada8f2acccd00eff56 up to, but not including, cc56c4d17721dcb10ad4e9c9266e449be1462683; 24d28e4f1271cb2f91613dada8f2acccd00eff56 up to, but not including, c8e639f5743cf4b01f8c65e0df075fe4d782b585; 24d28e4f1271cb2f91613dada8f2acccd00eff56 up to, but not including, eb988e46da2e4eae89f5337e047ce372fe33d5b1; and 1 more ranges | 2f236d8638f5b43e0c72919a6a27fe286c32053f, 50d12253666195a14c6cd2b81c376e2dbeedbdff, 6c71e065befb2fae8f1461559b940c04e1071bd5, 303766bb92c5c225cf40f9bbbe7e29749406e2f2, 7082b1fb5321037bc11ba1cf2d7ed23c6b2b521f, cc56c4d17721dcb10ad4e9c9266e449be1462683 |
| Linux | Linux Kernel | 4.18 up to, but not including, 4.19.299; 4.20 up to, but not including, 5.4.261; 5.5 up to, but not including, 5.10.201; 5.11 up to, but not including, 5.15.139; 5.16 up to, but not including, 6.1.63; 6.2 up to, but not including, 6.5.12; 6.6 up to, but not including, 6.6.2 | 4.19.299, 5.4.261, 5.10.201, 5.15.139, 6.1.63, 6.5.12 |
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.
Official description
In the Linux kernel, the following vulnerability has been resolved: Input: synaptics-rmi4 - fix use after free in rmi_unregister_function() The put_device() calls rmi_release_function() which frees "fn" so the dereference on the next line "fn->num_of_irqs" is a use after free. Move the put_device() to the end to fix this.
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/2f236d8638f5b43e0c72919a6a27fe286c32053f
- git.kernel.org/stable/c/303766bb92c5c225cf40f9bbbe7e29749406e2f2
- git.kernel.org/stable/c/50d12253666195a14c6cd2b81c376e2dbeedbdff
- git.kernel.org/stable/c/6c71e065befb2fae8f1461559b940c04e1071bd5
- git.kernel.org/stable/c/7082b1fb5321037bc11ba1cf2d7ed23c6b2b521f
- git.kernel.org/stable/c/c8e639f5743cf4b01f8c65e0df075fe4d782b585
- git.kernel.org/stable/c/cc56c4d17721dcb10ad4e9c9266e449be1462683
- git.kernel.org/stable/c/eb988e46da2e4eae89f5337e047ce372fe33d5b1
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
- 8.8 High severity
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