High · published August 15, 2026
In the Linux kernel, the following vulnerability has been resolved:
netfilter: xt_u32: reject invalid shift counts
u32_match_it() executes rule-supplied shift operands on a 32-bit
value. A malformed u32 rule can provide a shift count of 32 or more,
triggering an undefined shift out-of-bounds during packet evaluation.
Validate XT_U32_LEFTSH and XT_U32_RIGHTSH operands in
u32_mt_checkentry() and reject malformed rules before they reach the
packet path.