CVE-2023-35945 — Envoy is a cloud-native high-performance edge/middle/service proxy

Envoy is a cloud-native high-performance edge/middle/service proxy. Envoy’s HTTP/2 codec may leak a header map and bookkeeping structures upon receiving `RST_STREAM` immediately followed by the `GOAWAY` frames from an upstream server. In nghttp2, cleanup of pending requests due t

01What is this vulnerability?

Envoy is a cloud-native high-performance edge/middle/service proxy. Envoy’s HTTP/2 codec may leak a header map and bookkeeping structures upon receiving `RST_STREAM` immediately followed by the `GOAWAY` frames from an upstream server. In nghttp2, cleanup of pending requests due to receipt of the `GOAWAY` frame skips de-allocation of the bookkeeping structure and pending compressed header. The…

02Affected products

No structured affected-product list available — see references below for vendor advisories.

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2023-07-13T21:15:08.880
• Last modified: 2026-10-15T00:16:33.813

09References

• github.com — https://github.com/envoyproxy/envoy/security/advisories/GHSA-jfxv-29pc-x22r
• github.com — https://github.com/nghttp2/nghttp2/blob/e7f59406556c80904b81b593d38508591bb7523a…
• github.com — https://github.com/envoyproxy/envoy/security/advisories/GHSA-jfxv-29pc-x22r
• github.com — https://github.com/nghttp2/nghttp2/blob/e7f59406556c80904b81b593d38508591bb7523a…
• cert-portal.siemens.com — https://cert-portal.siemens.com/productcert/html/ssa-398330.html
• cert-portal.siemens.com — https://cert-portal.siemens.com/productcert/html/ssa-943925.html