Suricata flow: IPv4/IPv6 hash collision can reuse wrong flow state
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · High · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA suricata (OISF) Fixed in 8.0.6, 7.0.17
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2026-71855
References
Patch 3
More OISF Suricata vulnerabilities
- TI-2026-33506 ikev2: unbounded client transform storage can lead to resource exhaustion CVSS 3.1HIGH 7.5
- TI-2026-33484 Suricata lua/tls: null dereference in TlsGetCertInfo CVSS 3.1HIGH 7.5
- TI-2024-31811 Suricata ja4: invalid alpn leads to panic CVSS 3.1HIGH 7.5
- TI-2020-13673 Directory Traversal vulnerability found in Pfsense v.2.1.3 and Pfsense Suricata v.1.4.6… CVSS 3.1HIGH 7.5
- TI-2023-17928 In Suricata before 6.0.13, an adversary who controls an external source of Lua rules may… CVSS 3.1CRITICAL 9.8
- TI-2026-63304 Use after free in OISF Suricata CVSS 3.1CRITICAL 9.4
Sources
- CVE-2026-71855 · CVE Program
- CVE-2026-71855 · NVD
- FIRST EPSS
- CVE-2026-71855 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences