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Published: 9 June 2023

When gRPC HTTP2 stack raised a header size exceeded error, it skipped parsing the rest of the HPACK frame. This caused any HPACK table mutations to also be skipped, resulting in a desynchronization of HPACK tables between sender and receiver. If leveraged, say, between a proxy and a backend, this could lead to requests from the proxy being interpreted as containing headers from different proxy clients - leading to an information leak that can be used for privilege escalation or data exfiltration. We recommend upgrading beyond the commit contained in



Cvss 3 Severity Score


Score breakdown


Package Release Status
Launchpad, Ubuntu, Debian
bionic Needs triage

focal Needs triage

jammy Needs triage

kinetic Ignored
(end of life, was needs-triage)
lunar Ignored
(end of life, was needs-triage)
mantic Needs triage

noble Needs triage

trusty Does not exist

Released (1.54.2)
xenial Needs triage

Severity score breakdown

Parameter Value
Base score 7.5
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Scope Unchanged
Confidentiality High
Integrity impact None
Availability impact None
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N