Bug 2512097 (CVE-2026-73550)

Summary:	CVE-2026-73550 envoy: envoy: HTTP/2 memory exhaustion via discarded Host headers not counted in limits
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	kaycoth, security-response-team
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Deadline:	2026-08-26

Description OSIDB Bzimport 2026-08-06 15:01:55 UTC

An HTTP/2 memory-exhaustion issue where discarded duplicate Host headers were not included in request-header size and count limits. A downstream client could use repeated indexed Host values to cause excessive header copying and potentially terminate the Envoy process. Discarded Host headers are now included in the applicable limits.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (7.5)

Embargoed until 2026-08-26 13:00 GMT per Envoy upstream disclosure. PSIRTSUPT-21132.