Linux: Use After Free
CVE-2024-38630 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 948ed659c0151a605bd126da1e95f350ec5a7956, 9abe50e8492d1accd7d8dc17991179472d3d4573, 9b1c063ffc075abf56f63e55d70b9778ff534314 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 948ed659c0151a605bd126da1e95f350ec5a7956 or 9abe50e8492d1accd7d8dc17991179472d3d4573 or 9b1c063ffc075abf56f63e55d70b9778ff534314 or f19686d616500cd0d47b30cee82392b53f7f784a, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.6.33 or 6.9.4, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 948ed659c0151a605bd126da1e95f350ec5a7956; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 9abe50e8492d1accd7d8dc17991179472d3d4573; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 9b1c063ffc075abf56f63e55d70b9778ff534314; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, f19686d616500cd0d47b30cee82392b53f7f784a; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 573601521277119f2e2ba5f28ae6e87fc594f4d4; 2.6.12 | 948ed659c0151a605bd126da1e95f350ec5a7956, 9abe50e8492d1accd7d8dc17991179472d3d4573, 9b1c063ffc075abf56f63e55d70b9778ff534314, f19686d616500cd0d47b30cee82392b53f7f784a, 573601521277119f2e2ba5f28ae6e87fc594f4d4 |
| Linux | Linux Kernel | 3.8 up to, but not including, 6.6.33; 6.7 up to, but not including, 6.9.4 | 6.6.33, 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
- 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: watchdog: cpu5wdt.c: Fix use-after-free bug caused by cpu5wdt_trigger When the cpu5wdt module is removing, the origin code uses del_timer() to de-activate the timer. If the timer handler is running, del_timer() could not stop it and will return directly. If the port region is released by release_region() and then the timer handler cpu5wdt_trigger() calls outb() to write into the region that is released, the use-after-free bug will happen. Change del_timer() to timer_shutdown_sync() in order that the timer handler could be finished before the port region is released.
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
Other references
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
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- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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