CVE-2026-71855
oisf suricata
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.
Published 2026-09-18 · first seen here 2026-10-10
Analysis & write-ups
No technical write-up from a research team yet. Contact Zero checks Unit 42, Google/Mandiant, Microsoft, Talos, CrowdStrike, Rapid7, watchTowr and others several times a day, plus NVD and CISA reference links.
Where it shows in your logs
Server or web application · Unclassified weakness low confidence
What to look for
- The application's process (w3wp.exe, java, tomcat, node, php-fpm, httpd, python) starting shells or LOLBins (cmd, powershell, sh, bash, curl, wget, certutil)
- New script files in web roots (.jsp, .aspx, .php): a web shell
- Requests to unusual URLs on the application from internet IPs right before any of the above
- Outbound connections from the server to new external IPs
Data sources
Web server and WAF logs · ATT&CK DS0015 Application Log Content
- Sentinel
W3CIISLogAppServiceHTTPLogsAzureDiagnostics (Application Gateway / Front Door WAF)_Im_WebSession- Splunk
Web.Webms:iis:autoaccess_combinedWAF / proxy sourcetypes- CrowdStrike
Falcon Next-Gen SIEM: third-party web / WAF / proxy logs
Process creation · ATT&CK DS0009 Process Creation
- Sentinel
DeviceProcessEventsSecurityEvent (4688)Sysmon Event ID 1_Im_ProcessCreate- Splunk
Endpoint.ProcessesXmlWinEventLog:Microsoft-Windows-Sysmon/OperationalWinEventLog:Security (4688)- CrowdStrike
ProcessRollup2SyntheticProcessRollup2
File creation · ATT&CK DS0022 File Creation
- Sentinel
DeviceFileEventsSysmon Event ID 11_Im_FileEvent- Splunk
Endpoint.FilesystemSysmon Event ID 11- CrowdStrike
NewExecutableWrittenNewScriptWritten*FileWritten events
Network connections · ATT&CK DS0029 Network Connection Creation / Network Traffic Flow
- Sentinel
DeviceNetworkEventsCommonSecurityLog (firewall)_Im_NetworkSession- Splunk
Network_Traffic.All_TrafficFirewall sourcetypes (pan:traffic, fortigate_traffic, cisco:asa)- CrowdStrike
NetworkConnectIP4NetworkReceiveAcceptIP4NetworkConnectIP6
A generic baseline worked out from the product type and weakness (CWE-697), not a detection. Check table and field names against your environment. Hunt queries for Sigma, Splunk, Sentinel and CrowdStrike are coming.
References
- NVD entry
- 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