CVE-2026-74689 is a vulnerability in Linux Kernel
Published on August 22, 2026
net/atm: fix slab-out-of-bounds read in vcc_setsockopt()
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.
Products Associated with CVE-2026-74689
Want to know whenever a new CVE is published for Linux Kernel? stack.watch will email you.
Affected Versions
Linux:- Version 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and below b3bcd5d65ac03c15787b2a5b36c718e26a689336 is affected.
- Version 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and below 35f258fee9ed358c6d0f57f91c30bf029c3724af is affected.
- Version 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and below 6eb6af88710977eb529b558a07294874d8c40c4d is affected.
- Version 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and below 9f77c1ab382188f5b51982fab6d913443b6dc59f is affected.
- Version 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and below 2c5988c7349c0b64a7e0441bfc6e1dca54f7116a is affected.
- Version 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and below d0c80dbb970439bd2eeb0e5effff8c16a5f4e1e3 is affected.
- Version 2.6.12 is affected.
- Before 2.6.12 is unaffected.
- Version 6.1.183, <= 6.1.* is unaffected.
- Version 6.6.152, <= 6.6.* is unaffected.
- Version 6.12.104, <= 6.12.* is unaffected.
- Version 6.18.45, <= 6.18.* is unaffected.
- Version 7.1.9, <= 7.1.* is unaffected.
- Version 7.2, <= * is unaffected.