Linux: Use After Free
CVE-2024-44986 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 ae8512e93f4ce47614ca89defaec1b93e00697b8, 1504108cb6020df7b1a31c9bb80fd587470aa448, e891b36de161fcd96f12ff83667473e5067b9037 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 0.72% chance of exploitation within 30 days, higher than 55% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to ae8512e93f4ce47614ca89defaec1b93e00697b8 or 1504108cb6020df7b1a31c9bb80fd587470aa448 or e891b36de161fcd96f12ff83667473e5067b9037 or 3574d28caf9a09756ae87ad1ea096c6f47b6101e, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.4.289 or 5.10.233 or 5.15.166 or 6.1.107, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | ded37d03440d0ab346a8287cc2ba88b8dc90ceb0 up to, but not including, ae8512e93f4ce47614ca89defaec1b93e00697b8; 2323690eb05865a657709f4d28eb9538ea97bfc2 up to, but not including, 1504108cb6020df7b1a31c9bb80fd587470aa448; 5796015fa968a3349027a27dcd04c71d95c53ba5 up to, but not including, e891b36de161fcd96f12ff83667473e5067b9037; 5796015fa968a3349027a27dcd04c71d95c53ba5 up to, but not including, 3574d28caf9a09756ae87ad1ea096c6f47b6101e; 5796015fa968a3349027a27dcd04c71d95c53ba5 up to, but not including, 6ab6bf731354a6fdbaa617d1ec194960db61cf3b; 5796015fa968a3349027a27dcd04c71d95c53ba5 up to, but not including, 56efc253196751ece1fc535a5b582be127b0578a; 5796015fa968a3349027a27dcd04c71d95c53ba5 up to, but not including, da273b377ae0d9bd255281ed3c2adb228321687b; b34c668a867ffdcf8bd8db4a36512572e82b4a15; and 4 more ranges | ae8512e93f4ce47614ca89defaec1b93e00697b8, 1504108cb6020df7b1a31c9bb80fd587470aa448, e891b36de161fcd96f12ff83667473e5067b9037, 3574d28caf9a09756ae87ad1ea096c6f47b6101e, 6ab6bf731354a6fdbaa617d1ec194960db61cf3b, 56efc253196751ece1fc535a5b582be127b0578a |
| Debian | Debian Linux | 11.0 | Not stated |
| Linux | Linux Kernel | 5.4.137 up to, but not including, 5.4.289; 5.10.55 up to, but not including, 5.10.233; 5.13.7 up to, but not including, 5.15.166; 5.16 up to, but not including, 6.1.107; 6.2 up to, but not including, 6.6.48; 6.7 up to, but not including, 6.10.7; 6.11 | 5.4.289, 5.10.233, 5.15.166, 6.1.107, 6.6.48, 6.10.7 |
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 | 8.1 | High | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
In the Linux kernel, the following vulnerability has been resolved: ipv6: fix possible UAF in ip6_finish_output2() If skb_expand_head() returns NULL, skb has been freed and associated dst/idev could also have been freed. We need to hold rcu_read_lock() to make sure the dst and associated idev are alive.
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/3574d28caf9a09756ae87ad1ea096c6f47b6101e
- git.kernel.org/stable/c/56efc253196751ece1fc535a5b582be127b0578a
- git.kernel.org/stable/c/6ab6bf731354a6fdbaa617d1ec194960db61cf3b
- git.kernel.org/stable/c/da273b377ae0d9bd255281ed3c2adb228321687b
- git.kernel.org/stable/c/e891b36de161fcd96f12ff83667473e5067b9037
Third-party and government advisories
- lists.debian.org/debian-lts-announce/2025/01/msg00001.htmlMailing List, Third Party Advisory
Other references
Recent Use After Free vulnerabilities
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