CVE-2026-74564: In the Linux kernel, the following vulnerability has been resolved: netfilter: xt_hashlimit: validate hashtable support
Summary
A vulnerability in the Linux kernel's netfilter xt_hashlimit module could allow uninitialized memory access when the XT_HASHLIMIT_RATE_MATCH flag (a setting that changes how the rate-limiting hashtable stores data) is used inconsistently across multiple rules on the same hashtable. The issue occurs because different rules might interpret the same memory layout differently, leading to access of uninitialized data.
Solution / Mitigation
Update the .checkentry validation path (the code that checks rule configuration when rules are added) to verify that if XT_HASHLIMIT_RATE_MATCH mode is used, all rules referring to the same hashtable must request it consistently. Additionally, reject the XT_HASHLIMIT_RATE_MATCH flag if it is set on revision versions less than 3.
Vulnerability Details
EPSS: 0.0%
August 15, 2026
Classification
Original source: https://nvd.nist.gov/vuln/detail/CVE-2026-74564
First tracked: August 15, 2026 at 02:08 PM
Classified by LLM (prompt v3) · confidence: 95%