Bug 2538956 (CVE-2026-71418)

Summary: CVE-2026-71418 suricata: Suricata: Denial of Service via crafted HTTP/2 DATA frames
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Priority: high    
Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in Suricata, a network Intrusion Detection System, Intrusion Prevention System, and Network Security Monitoring engine. Its DNS-over-HTTP/2 processing incorrectly retains previously processed HTTP/2 DATA frame contents. A remote attacker can exploit this by sending multiple crafted HTTP/2 DATA frames with the EndOfStream flag set. This causes the internal buffer to grow and reprocess prior contents, leading to quadratic CPU consumption. This can result in degraded packet processing, loss of monitoring visibility, or a denial of service (DoS) condition.
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Bug Depends On: 2539206    
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Description OSIDB Bzimport 2026-09-22 21:49:20 UTC 
Suricata is a network Intrusion Detection System, Intrusion Prevention System and Network Security Monitoring engine. From 8.0.0 until 8.0.6, DNS-over-HTTP/2 processing in rust/src/http2/http2.rs retains previously processed HTTP/2 DATA frame contents instead of clearing the internal buffer. Multiple DATA frames with the EndOfStream flag set can grow the buffer to its 65 KiB limit while causing all prior contents to be processed again, producing quadratic CPU complexity, degraded packet processing, loss of monitoring visibility, or denial of service. This issue is fixed in version 8.0.6.