CVE-2026-72350
HighCVSS 7.8Exploitation Probability (EPSS)
Low risk7th percentile - higher than 7% of all known CVEs
Summary
In the Linux kernel, the netfilter xt_u32 module lacks validation of shift counts supplied by rules. A malformed rule can provide a shift count of 32 or more, triggering an undefined shift out-of-bounds during packet evaluation. Validation of XT_U32_LEFTSH and XT_U32_RIGHTSH operands was added in u32_mt_checkentry() to reject malformed rules before they reach the packet path.
Risk Assessment
Malformed rules can cause kernel crashes or unpredictable behavior during packet processing, potentially leading to service disruption or security bypass.
Recommendation
Apply the Linux kernel update containing the fix for CVE-2026-72350. Before deployment, verify that xt_u32 rules are valid.
Original NVD description (English source)
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.