Linux: Use After Free
CVE-2023-52491 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 43872f44eee6c6781fea1348b38885d8e78face9, 1b1036c60a37a30caf6759a90fe5ecd06ec35590, 9fec4db7fff54d9b0306a332bab31eac47eeb5f6 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 43872f44eee6c6781fea1348b38885d8e78face9 or 1b1036c60a37a30caf6759a90fe5ecd06ec35590 or 9fec4db7fff54d9b0306a332bab31eac47eeb5f6 or 8254d54d00eb6cdb8367399c7f912eb8d354ecd7, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.210 or 5.15.149 or 6.1.76 or 6.6.15, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | b2f0d2724ba477d326e9d654d4db1c93e98f8b93 up to, but not including, 43872f44eee6c6781fea1348b38885d8e78face9; b2f0d2724ba477d326e9d654d4db1c93e98f8b93 up to, but not including, 1b1036c60a37a30caf6759a90fe5ecd06ec35590; b2f0d2724ba477d326e9d654d4db1c93e98f8b93 up to, but not including, 9fec4db7fff54d9b0306a332bab31eac47eeb5f6; b2f0d2724ba477d326e9d654d4db1c93e98f8b93 up to, but not including, 8254d54d00eb6cdb8367399c7f912eb8d354ecd7; b2f0d2724ba477d326e9d654d4db1c93e98f8b93 up to, but not including, 6e2f37022f0fc0893da4d85a0500c9d547fffd4c; b2f0d2724ba477d326e9d654d4db1c93e98f8b93 up to, but not including, 206c857dd17d4d026de85866f1b5f0969f2a109e; 4.12 | 43872f44eee6c6781fea1348b38885d8e78face9, 1b1036c60a37a30caf6759a90fe5ecd06ec35590, 9fec4db7fff54d9b0306a332bab31eac47eeb5f6, 8254d54d00eb6cdb8367399c7f912eb8d354ecd7, 6e2f37022f0fc0893da4d85a0500c9d547fffd4c, 206c857dd17d4d026de85866f1b5f0969f2a109e |
| Linux | Linux Kernel | 4.12 up to, but not including, 5.10.210; 5.11 up to, but not including, 5.15.149; 5.16 up to, but not including, 6.1.76; 6.2 up to, but not including, 6.6.15; 6.7 up to, but not including, 6.7.3 | 5.10.210, 5.15.149, 6.1.76, 6.6.15, 6.7.3 |
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: media: mtk-jpeg: Fix use after free bug due to error path handling in mtk_jpeg_dec_device_run In mtk_jpeg_probe, &jpeg->job_timeout_work is bound with mtk_jpeg_job_timeout_work. In mtk_jpeg_dec_device_run, if error happens in mtk_jpeg_set_dec_dst, it will finally start the worker while mark the job as finished by invoking v4l2_m2m_job_finish. There are two methods to trigger the bug. If we remove the module, it which will call mtk_jpeg_remove to make cleanup. The possible sequence is as follows, which will cause a use-after-free bug. CPU0 CPU1 mtk_jpeg_dec_... | start worker | |mtk_jpeg_job_timeout_work mtk_jpeg_remove | v4l2_m2m_release | kfree(m2m_dev); | | | v4l2_m2m_get_curr_priv | m2m_dev->curr_ctx //use If we close the file descriptor, which will call mtk_jpeg_release, it will have a similar sequence. Fix this bug by starting timeout worker only if started jpegdec worker successfully. Then v4l2_m2m_job_finish will only be called in either mtk_jpeg_job_timeout_work or mtk_jpeg_dec_device_run.
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/1b1036c60a37a30caf6759a90fe5ecd06ec35590
- git.kernel.org/stable/c/206c857dd17d4d026de85866f1b5f0969f2a109e
- git.kernel.org/stable/c/43872f44eee6c6781fea1348b38885d8e78face9
- git.kernel.org/stable/c/6e2f37022f0fc0893da4d85a0500c9d547fffd4c
- git.kernel.org/stable/c/8254d54d00eb6cdb8367399c7f912eb8d354ecd7
- git.kernel.org/stable/c/9fec4db7fff54d9b0306a332bab31eac47eeb5f6
- lists.debian.org/debian-lts-announce/2024/06/msg00017.html
Recent Use After Free vulnerabilities
- 8.4 High severity
- 8.4 High severity
- 8.4 High severity
- 7.8 High severity
- 7.8 High severity
- 9.1 Critical severity
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