CVE-2026-94083
Received Received - Intake

Suricata DoH2 Type Confusion Leading to Invalid Free

Publication date: 2026-09-20

Last updated on: 2026-09-20

Assigner: MITRE

Description
Suricata before 8.0.7 has a DoH2 type confusion that can cause an invalid free, because cleanup code for the HTTP2 state is executed even though the actual state is HTTP1 (when there is a DoH2 request with an HTTP1 to HTTP2 upgrade). This requires app-layer.protocols.doh2 to be enabled, which is the default in 8.x versions.

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Meta Information

Published
2026-09-20
Last Modified
2026-09-20
Generated
2026-09-20
AI Q&A
2026-09-20
EPSS Evaluated
N/A
NVD
CVE-2026-94083
EUVD
EUVD-2026-83638

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
oisf suricata to 8.0.7 (exc)

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-843 The product allocates or initializes a resource such as a pointer, object, or variable using one type, but it later accesses that resource using a type that is incompatible with the original type.

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Executive Summary

This vulnerability is a type confusion in Suricata versions before 8.0.7 that occurs during DoH2 (DNS over HTTPS version 2) protocol handling. When a client sends a DoH2 request with an HTTP1 to HTTP2 upgrade in a single packet, Suricata incorrectly attempts to clean up HTTP2 state even though the actual state remains HTTP1. This happens because the cleanup code runs despite the protocol not being fully upgraded, leading to an invalid memory free operation.

Detection Guidance

This vulnerability can be detected by checking Suricata version and monitoring for crashes or errors related to HTTP1 to HTTP2 to DoH2 protocol upgrades. Upgrade to Suricata 8.0.7 or later to address the issue.

Impact Analysis

This vulnerability could allow remote attackers to cause a denial of service by crashing Suricata through a crafted packet. Since Suricata is a network threat detection engine, its failure could disrupt network monitoring and security operations. The impact is limited to systems running vulnerable versions with the app-layer.protocols.doh2 setting enabled, which is default in Suricata 8.x.

Mitigation Strategies

Immediately upgrade Suricata to version 8.0.7 or later. Disable app-layer.protocols.doh2 if not required, as this vulnerability is triggered when this setting is enabled.

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