Linux: Use After Free
CVE-2022-48791 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 d872e7b5fe38f325f5206b6872746fa02c2b4819, 3c334cdfd94945b8edb94022a0371a8665b17366, 510b21442c3a2e3ecc071ba3e666b320e7acdd61 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 0.25% 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 d872e7b5fe38f325f5206b6872746fa02c2b4819 or 3c334cdfd94945b8edb94022a0371a8665b17366 or 510b21442c3a2e3ecc071ba3e666b320e7acdd61 or 61f162aa4381845acbdc7f2be4dfb694d027c018, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.102 or 5.15.25 or 5.16.11, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 968ee9176a4489ce6d5ee54ff88dadfbff9b95f4 up to, but not including, d872e7b5fe38f325f5206b6872746fa02c2b4819; d712d3fb484b7fa8d1d57e9ca6f134bb9d8c18b1 up to, but not including, 3c334cdfd94945b8edb94022a0371a8665b17366; d712d3fb484b7fa8d1d57e9ca6f134bb9d8c18b1 up to, but not including, 510b21442c3a2e3ecc071ba3e666b320e7acdd61; d712d3fb484b7fa8d1d57e9ca6f134bb9d8c18b1 up to, but not including, 61f162aa4381845acbdc7f2be4dfb694d027c018; fa3c19ceaa8b4b7c29d710c2c407df57d256a6c5; 5.10.61 up to, but not including, 5.10.102; 5.13.13 up to, but not including, 5.14; 5.14 | d872e7b5fe38f325f5206b6872746fa02c2b4819, 3c334cdfd94945b8edb94022a0371a8665b17366, 510b21442c3a2e3ecc071ba3e666b320e7acdd61, 61f162aa4381845acbdc7f2be4dfb694d027c018, 5.10.102, 5.14 |
| Linux | Linux Kernel | before 5.10.102; 5.11 up to, but not including, 5.15.25; 5.16 up to, but not including, 5.16.11 | 5.10.102, 5.15.25, 5.16.11 |
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 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: scsi: pm8001: Fix use-after-free for aborted TMF sas_task Currently a use-after-free may occur if a TMF sas_task is aborted before we handle the IO completion in mpi_ssp_completion(). The abort occurs due to timeout. When the timeout occurs, the SAS_TASK_STATE_ABORTED flag is set and the sas_task is freed in pm8001_exec_internal_tmf_task(). However, if the I/O completion occurs later, the I/O completion still thinks that the sas_task is available. Fix this by clearing the ccb->task if the TMF times out - the I/O completion handler does nothing if this pointer is cleared.
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
Recent Use After Free vulnerabilities
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
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