CVE-2024-40909: Linux kernel · bpf: Fix a potential use-after-free in bpf_link_free()
Source GCVE Database
Not known to be exploited · CVSS 7.8 High.
Data as of 30 Oct 2026, 16:33 UTC
Thin evidence
One scorer or none| CNA (Linux) | CVSS 3.1 | 7.8 |
|---|
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 12 Jul 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
Description
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix a potential use-after-free in bpf_link_free() After commit 1a80dbcb2dba, bpf_link can be freed by link->ops->dealloc_deferred, but the code still tests and uses link->ops->dealloc afterward, which leads to a use-after-free as reported by syzbot. Actually, one of them should be sufficient, so just call one of them instead of both. Also add a WARN_ON() in case of any problematic implementation.
References
- nvd.nist.gov/vuln/detail/CVE-2024-40909 (opens in a new tab)
- git.kernel.org/stable/c/2884dc7d08d98a89d8d65121524bb7533183a63a (opens in a new tab)
- git.kernel.org/stable/c/91cff53136daeff50816b0baeafd38a6976f6209 (opens in a new tab)
- git.kernel.org/stable/c/e8ccda39b395169622855607085cdeef4d376e0f (opens in a new tab)
- git.kernel.org/stable/c/fa97b8fed9896f1e89cb657513e483a152d4c382 (opens in a new tab)