What’s Vulnerable › Vulnerabilities

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

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-18 · updated 2026-09-28
• Weakness: CWE-697

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 products

• OISF suricata: before 7.0.17; from 8.0.0 before 8.0.6 — fixed in 7.0.17, 8.0.6

How to fix

Upgrade to a fixed version: OISF suricata 7.0.17, 8.0.6. Check the vendor advisory for mitigations.

References

• https://github.com/OISF/suricata/commit/181b3b2fdd1fe87e4534de4fc79e29a083ef125f
• https://github.com/OISF/suricata/commit/4e2f23d031fbcfd72883bacd3d723c9874f23701
• https://github.com/OISF/suricata/commit/bc41dcc854e24487d3786ce578a8a86a8350ab20
• https://github.com/OISF/suricata/releases/tag/suricata-7.0.17
• https://github.com/OISF/suricata/releases/tag/suricata-8.0.6
• https://github.com/OISF/suricata/security/advisories/GHSA-fvwh-wjcq-2586
• https://redmine.openinfosecfoundation.org/issues/8558

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