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Vulnerability · Published Sep 18, 2026 · Assigned by GitHub_M

CVE-2026-71855Suricata flow: IPv4/IPv6 hash collision can reuse wrong flow state

Medium 5.9

In plain English

A medium-severity security flaw in suricata from OISF. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 24% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.9Medium
Exploit odds (30 days)0.3%top 76.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

Suricata is a network Intrusion Detection System, Intrusion Prevention System and Network Security Monitoring engine. Prior to 7.0.17 and 8.0.6, src/flow-hash.c can treat an IPv4 and IPv6 flow as equal without comparing the IP family when their raw address words, ports, protocol, VLAN, recursion level, live device, and hash bucket align. An IPv6 packet can therefore reuse IPv4 flow state or the reverse, causing incorrect flowbit state, detection bypass, or IP-only bypass. This issue is fixed in versions 8.0.6 and 7.0.17.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:13suricatano fix listedDEBIAN-CVE-2026-71855
Debian:14suricata1:8.0.6-1DEBIAN-CVE-2026-71855
Ubuntu:22.04:LTSsuricatano fix listedUBUNTU-CVE-2026-71855
Ubuntu:24.04:LTSsuricatano fix listedUBUNTU-CVE-2026-71855
Ubuntu:26.04:LTSsuricatano fix listedUBUNTU-CVE-2026-71855

Affected products (as reported)

VendorProductVersions
OISF suricata >= 8.0.0, < 8.0.6< 7.0.17

Weakness: CWE-697 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

References