v1.35.12

Mail-0/Zerov1.35.12Jun 10, 2026by publish-envoy[bot]

AI Summary

This Envoy release fixes the runtime guard bug and adds HTTP/2 statistics and cookie limit features.

Key Highlights

Fixed RTDS runtime guard override removal
Added HTTP/2 header statistics histograms
Added HTTP/2 cookie size limit configuration

New Features

HTTP/2 header statistics histograms
HTTP/2 cookie size limit configuration

Full Release Notes

**Summary of changes**:

* Bug fixes:
  - runtime: fixed RTDS runtime guard override removal so deleting an override restores the process-wide runtime guard value to the default value.

* New features:
  - http2: added opt-in histograms for HTTP/2 header statistics, including header-entry count, header-map byte size, reassembled ``cookie`` header length, and individual ``cookie`` header count. Enable with ``envoy.reloadable_features.http2_record_histograms``; the histograms and runtime guard will be removed in a future Envoy release.
  - http2: added ``envoy.reloadable_features.http2_max_cookies_size_in_kb`` to limit the size of the reassembled ``cookie`` header. By default, no cookie-size limit is enforced.

**Docker images**:
    https://hub.docker.com/r/envoyproxy/envoy/tags?page=1&name=v1.35.12
**Docs**:
    https://www.envoyproxy.io/docs/envoy/v1.35.12/
**Release notes**:
    https://www.envoyproxy.io/docs/envoy/v1.35.12/version_history/v1.35/v1.35.12
**Full changelog**:
    https://github.com/envoyproxy/envoy/compare/v1.35.11...v1.35.12

Signed-off-by: Ryan Northey [ryan@synca.io](mailto:ryan@synca.io)
Signed-off-by: Kateryna Nezdolii [kateryna.nezdolii@gmail.com](mailto:kateryna.nezdolii@gmail.com)