Is CVE-2026-71855 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-71855 being exploited in the wild.

How severe is CVE-2026-71855?

Medium severity, with a CVSS score of 5.9, published 18 September 2026.

Which products and versions are affected?

OISF Suricata before 7.0.17 and before 8.0.6.

Is there a fix for CVE-2026-71855?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-71855 attacked?

It is attacked over the network, in a hosted service.

Am I affected by CVE-2026-71855?

Check whether you run OISF Suricata at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-71855: Suricata IP family validation bypass in flow comparison

CVE-2026-71855 · Severity: medium · CVSS 5.9 · Published 2026-09-18

Suricata is a network security monitoring engine that detects and prevents intrusions. Due to inadequate IP family validation in flow hash comparison, an attacker can craft packets that reuse flow state across IPv4 and IPv6 traffic, causing security rules to be bypassed and intrusions to go undetected. This allows malicious network traffic to evade detection entirely.

Technologies: OISF Suricata. Vendors: OISF.

Quick answers

Is CVE-2026-71855 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-71855 being exploited in the wild.
How severe is CVE-2026-71855?: Medium severity, with a CVSS score of 5.9, published 18 September 2026.
Which products and versions are affected?: OISF Suricata before 7.0.17 and before 8.0.6.
Is there a fix for CVE-2026-71855?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-71855 attacked?: It is attacked over the network, in a hosted service.
Am I affected by CVE-2026-71855?: Check whether you run OISF Suricata at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The vulnerability exists in src/flow-hash.c where IPv4 and IPv6 flows are compared without verifying the IP family version, despite matching address words, ports, protocol, VLAN, and other attributes. An attacker can send IPv6 packets that reuse IPv4 flow state (or vice versa), bypassing flowbit state checks and detection rules. The flaw is fixed by explicitly comparing the IP family version before treating flows as equivalent.

Affected products

OISF Suricata before 7.0.17 and before 8.0.6

Timeline

2026-09-18: disclosed

References

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