Linux: Use After Free
CVE-2024-49852 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 16a570f07d870a285b0c0b0d1ca4dff79e8aa5ff, abc71e89170ed32ecf0a5a29f31aa711e143e941, baeb8628ab7f4577740f00e439d3fdf7c876b0ff 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 0.21% 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 16a570f07d870a285b0c0b0d1ca4dff79e8aa5ff or abc71e89170ed32ecf0a5a29f31aa711e143e941 or baeb8628ab7f4577740f00e439d3fdf7c876b0ff or 7c2908985e4ae0ea1b526b3916de9e5351650908, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.15.168 or 6.1.113 or 6.6.54 or 6.10.13, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | fcd427303eb90aa3cb08e7e0b68e0e67a6d47346 up to, but not including, 16a570f07d870a285b0c0b0d1ca4dff79e8aa5ff; fcd427303eb90aa3cb08e7e0b68e0e67a6d47346 up to, but not including, abc71e89170ed32ecf0a5a29f31aa711e143e941; fcd427303eb90aa3cb08e7e0b68e0e67a6d47346 up to, but not including, baeb8628ab7f4577740f00e439d3fdf7c876b0ff; fcd427303eb90aa3cb08e7e0b68e0e67a6d47346 up to, but not including, 7c2908985e4ae0ea1b526b3916de9e5351650908; fcd427303eb90aa3cb08e7e0b68e0e67a6d47346 up to, but not including, 98752fcd076a8cbc978016eae7125b4971be1eec; fcd427303eb90aa3cb08e7e0b68e0e67a6d47346 up to, but not including, 2e4b02fad094976763af08fec2c620f4f8edd9ae; 5.14 | 16a570f07d870a285b0c0b0d1ca4dff79e8aa5ff, abc71e89170ed32ecf0a5a29f31aa711e143e941, baeb8628ab7f4577740f00e439d3fdf7c876b0ff, 7c2908985e4ae0ea1b526b3916de9e5351650908, 98752fcd076a8cbc978016eae7125b4971be1eec, 2e4b02fad094976763af08fec2c620f4f8edd9ae |
| Linux | Linux Kernel | 5.14 up to, but not including, 5.15.168; 5.16 up to, but not including, 6.1.113; 6.2 up to, but not including, 6.6.54; 6.7 up to, but not including, 6.10.13; 6.11 up to, but not including, 6.11.2 | 5.15.168, 6.1.113, 6.6.54, 6.10.13, 6.11.2 |
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: scsi: elx: libefc: Fix potential use after free in efc_nport_vport_del() The kref_put() function will call nport->release if the refcount drops to zero. The nport->release release function is _efc_nport_free() which frees "nport". But then we dereference "nport" on the next line which is a use after free. Re-order these lines to avoid the use after free.
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/16a570f07d870a285b0c0b0d1ca4dff79e8aa5ff
- git.kernel.org/stable/c/2e4b02fad094976763af08fec2c620f4f8edd9ae
- git.kernel.org/stable/c/7c2908985e4ae0ea1b526b3916de9e5351650908
- git.kernel.org/stable/c/98752fcd076a8cbc978016eae7125b4971be1eec
- git.kernel.org/stable/c/abc71e89170ed32ecf0a5a29f31aa711e143e941
- git.kernel.org/stable/c/baeb8628ab7f4577740f00e439d3fdf7c876b0ff
Other references
Recent Use After Free vulnerabilities
- 7.0 High severity
- 7.0 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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