[26.6] Align the HTTP/2 max header list size with the HTTP/1.1 max header size - #51497
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(keycloak#51246) Keycloak configures quarkus.http.limits.max-header-size=65535 for HTTP/1.1 but never sets max-header-list-size so HTTP/2 requests were held to the much smaller Quarkus default, as noted in the original issue. Any request with headers between the two limits succeeded over HTTP/1.1 but was rejected at the HTTP/2 codec with no HTTP response and nothing logged. This aligns the HTTP/2 limit with HTTP/1.1 and adds an integration test covering large headers over both protocols. Closes keycloak#51182 Signed-off-by: James Gore <83005220+thejamesgore@users.noreply.github.com> (cherry picked from commit 506df74)
vmuzikar
approved these changes
Aug 7, 2026
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(#51246)
Keycloak configures quarkus.http.limits.max-header-size=65535 for HTTP/1.1 but never sets max-header-list-size so HTTP/2 requests were held to the much smaller Quarkus default, as noted in the original issue. Any request with headers between the two limits succeeded over HTTP/1.1 but was rejected at the HTTP/2 codec with no HTTP response and nothing logged. This aligns the HTTP/2 limit with HTTP/1.1 and adds an integration test covering large headers over both protocols.
Closes #51182
Signed-off-by: James Gore
83005220+thejamesgore@users.noreply.github.com
(cherry picked from commit 506df74)