High severity · published Sep 18, 2026
CVE-2026-71855
Suricata flow: IPv4/IPv6 hash collision can reuse wrong flow state
7.5
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 24% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
SU
suricata · OISF
>= 8.0.0, < 8.0.6; < 7.0.17 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-71855
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-71855
Patch
https://github.com/OISF/suricata/commit/181b3b2fdd1fe87e4534de4fc79e29a083ef125f
Patch
https://github.com/OISF/suricata/commit/4e2f23d031fbcfd72883bacd3d723c9874f23701
Patch
https://github.com/OISF/suricata/commit/bc41dcc854e24487d3786ce578a8a86a8350ab20
Release Notes
https://github.com/OISF/suricata/releases/tag/suricata-7.0.17
Release Notes
https://github.com/OISF/suricata/releases/tag/suricata-8.0.6
Vendor Advisory
https://github.com/OISF/suricata/security/advisories/GHSA-fvwh-wjcq-2586
More from suricata
9.8
CVE-2026-22262
Suricata datasets: stack overflow when saving a set
9.8
CVE-2023-35853
In Suricata before 6.0.13, an adversary who controls an external source of Lua rules may be able to execute Lua code
9.8
CVE-2021-37592
Suricata before 5.0.8 and 6.x before 6.0.4 allows TCP evasion via a client with a crafted TCP/IP stack that can send a certain sequence of segments
9.8
CVE-2018-10244
Suricata version 4.0.4 incorrectly handles the parsing of an EtherNet/IP PDU
9.4
CVE-2026-94084
Suricata before 8.0.7 has an Http2ThreadMultiBuf use-after-free when a transaction is inspected by rules that use http.response_header with and without a transform