In proxygen's HTTP/3 session, when a HEADERS block referenced QPACK dynamic table entries that had not yet been received, header decoding for that stream was paused, but the session continued to read the stream from the QUIC transport. The unread data bypassed the session's ingress buffer limit, returned flow-control credit to the peer, and was re-scanned in full on every read. With QPACK blocked streams enabled (the default), a remote, unauthenticated HTTP/3 peer could send a HEADERS block that references a dynamic table insert it never sends, followed by a continuous stream of data, causing memory growth until the request timed out and CPU usage that grows quadratically, leading to denial of service. This issue affects proxygen versions prior to v2026.11.09.00.
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History

Wed, 11 Nov 2026 17:00:00 +0000

Type Values Removed Values Added
Description In proxygen's HTTP/3 session, when a HEADERS block referenced QPACK dynamic table entries that had not yet been received, header decoding for that stream was paused, but the session continued to read the stream from the QUIC transport. The unread data bypassed the session's ingress buffer limit, returned flow-control credit to the peer, and was re-scanned in full on every read. With QPACK blocked streams enabled (the default), a remote, unauthenticated HTTP/3 peer could send a HEADERS block that references a dynamic table insert it never sends, followed by a continuous stream of data, causing memory growth until the request timed out and CPU usage that grows quadratically, leading to denial of service. This issue affects proxygen versions prior to v2026.11.09.00.
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cve-icon MITRE

Status: PUBLISHED

Assigner: Meta

Published:

Updated: 2026-11-11T16:55:20.571Z

Reserved: 2026-10-29T17:01:32.523Z

Link: CVE-2026-119237

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2026-11-11T17:17:16.917

Modified: 2026-11-11T17:17:17.017

Link: CVE-2026-119237

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

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Weaknesses

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