Linux: Unchecked Return Value
CVE-2024-39492 is a high-severity unchecked return value vulnerability in Linux, with a CVSS 3.1 base score of 7.0 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 2d42a37a4518478f075ccf848242b4a50e313a46, 747a69a119c469121385543f21c2d08562968ccc 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 0.19% 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 2d42a37a4518478f075ccf848242b4a50e313a46 or 747a69a119c469121385543f21c2d08562968ccc, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.9.4 or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 8afe816b0c9944a11adb12628e3b700a08a55d52 up to, but not including, 2d42a37a4518478f075ccf848242b4a50e313a46; 8afe816b0c9944a11adb12628e3b700a08a55d52 up to, but not including, 747a69a119c469121385543f21c2d08562968ccc; 6.7 | 2d42a37a4518478f075ccf848242b4a50e313a46, 747a69a119c469121385543f21c2d08562968ccc |
| Linux | Linux Kernel | 6.7 up to, but not including, 6.9.4 | 6.9.4 |
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
- HighSuccess depends on conditions outside the attacker's control.
- 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:H/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CISA (ADP).
Official description
In the Linux kernel, the following vulnerability has been resolved: mailbox: mtk-cmdq: Fix pm_runtime_get_sync() warning in mbox shutdown The return value of pm_runtime_get_sync() in cmdq_mbox_shutdown() will return 1 when pm runtime state is active, and we don't want to get the warning message in this case. So we change the return value < 0 for WARN_ON().
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Unchecked Return Value
The product does not check the return value from a method or function.
How developers prevent this class of flaw
- Check the results of all functions that return a value and verify that the value is expected.
- For any pointers that could have been modified or provided from a function that can return NULL, check the pointer for NULL before use. When working with a multithreaded or otherwise asynchronous environment, ensure that proper locking APIs are used to lock before the check, and unlock when it has finished.
- Ensure that you account for all possible return values from the function.
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 Unchecked Return Value vulnerabilities
- 8.8 High severity
- 7.5 High severity
- 7.6 High severity
- 7.5 High severity
- 8.8 High severity
- 7.8 High severity
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