CVE-2026-74689: Linux kernel · net/atm: fix slab-out-of-bounds read in vcc_setsockopt()
Source GCVE Database
Not known to be exploited · CVSS 7.1 High.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 3% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 22 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 2026.
Description
In the Linux kernel, the following vulnerability has been resolved: net/atm: fix slab-out-of-bounds read in vcc_setsockopt() vcc_setsockopt() contained an ineffective optlen check: if (__SO_LEVEL_MATCH(optname, level) && optlen != __SO_SIZE(optname)) return -EINVAL; If __SO_LEVEL_MATCH(optname, level) evaluated to false (e.g. if the caller passed a mismatched level), the length check optlen != __SO_SIZE(optname) was short-circuited and bypassed. Execution then fell through to switch(optname), calling copy_from_sockptr() assuming optval contained sufficient space. Furthermore, even if level matched, a cgroup BPF setsockopt filter could shrink optlen after entry. Because copy_from_sockptr() on kernel pointers uses memcpy(), this leads to a KASAN slab-out-of-bounds read when optlen is smaller than the expected structure size. Fix this by using copy_safe_from_sockptr(), which unconditionally validates that optlen is at least the expected size before copying. Also change the local 'value' variable type from 'unsigned long' to 'int' so that SO_SETCLP matches its sizeof(int) ABI encoding on 64-bit systems.
References
- nvd.nist.gov/vuln/detail/CVE-2026-74689 (opens in a new tab)
- git.kernel.org/stable/c/2c5988c7349c0b64a7e0441bfc6e1dca54f7116a (opens in a new tab)
- git.kernel.org/stable/c/35f258fee9ed358c6d0f57f91c30bf029c3724af (opens in a new tab)
- git.kernel.org/stable/c/6eb6af88710977eb529b558a07294874d8c40c4d (opens in a new tab)
- git.kernel.org/stable/c/9f77c1ab382188f5b51982fab6d913443b6dc59f (opens in a new tab)
- git.kernel.org/stable/c/b3bcd5d65ac03c15787b2a5b36c718e26a689336 (opens in a new tab)
- git.kernel.org/stable/c/d0c80dbb970439bd2eeb0e5effff8c16a5f4e1e3 (opens in a new tab)