CVE-2026-71855 (CVSS 5.9)

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.

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CVSS v3.1 Score

5.9

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS — Exploit Prediction

0.0031

Probability of exploitation

0.22%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-697 CWE-697

References

Other 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

Frequently Asked Questions

What is CVE-2026-71855? +

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. It has a CVSS v3.1 base score of 5.9 (MEDIUM).

How severe is CVE-2026-71855? +

CVE-2026-71855 has a CVSS v3.1 score of 5.9 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0031, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-71855? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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