AIKIDO-2026-11043
mod_http2 is vulnerable to Resource Exhaustion
75
High Risk
This Affects:
mod_http2TL;DR
mod_http2 merges split HTTP/2 Cookie header fields but does not count merged cookie crumbs against LimitRequestFields. A client can send many HPACK-indexed cookie fragments and stall the response stream, causing Apache to repeatedly rebuild and retain large header allocations. Pre-fix servers can suffer remote memory exhaustion and availability loss through HTTP/2 requests. The fix treats merged cookie headers as added fields so they are limited by LimitRequestFields.
Who does this affect?
You are affected if you are using a version that falls within the vulnerable range.
Background info
mod_http2 is vulnerable to Resource Exhaustion in versions 2.0.0 - 2.0.40.
How to fix this
Upgrade the mod_http2 library to the patch version.
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SOC 2Compliant
ISO 27001Compliant