CVE-2023-35945: Envoy vulnerable to HTTP/2 memory leak in nghttp2 codec
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 RSTSTREAM 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 error return [code path] is taken if connection is already marked for not sending more requests due to GOAWAY frame. The clean-up code is right after the return statement, causing memory leak. Denial of service through memory exhaustion. This vulnerability was patched in versions(s) 1.26.3, 1.25.8, 1.24.9, 1.23.11.
Other sources
Envoy vulnerable to HTTP/2 memory leak in nghttp2 codec
— Microsoft
Specifically crafter response from an untrusted upstream service can cause the denial of service through memory exhaustion. This is caused by Envoy’s HTTP/2 codec may leak a header map and bookkeeping structures upon receiving RSTSTREAM immediately followed by the GOAWAY frames from an upstream server.
— Red Hat
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
redhat/envoyto a version that resolves this vulnerability.Fixed in 1.26.3 - Upgrade
Upgrade
redhat/envoyto a version that resolves this vulnerability.Fixed in 1.25.8 - Upgrade
Upgrade
redhat/envoyto a version that resolves this vulnerability.Fixed in 1.24.9 - Upgrade
Upgrade
redhat/envoyto a version that resolves this vulnerability.Fixed in 1.23.11 - Upgrade
Upgrade
Envoyto a version that resolves this vulnerability.Fixed in 1.26.3 - Upgrade
Upgrade
Envoyto a version that resolves this vulnerability.Fixed in 1.25.8 - Upgrade
Upgrade
Envoyto a version that resolves this vulnerability.Fixed in 1.24.9 - Upgrade
Upgrade
Envoyto a version that resolves this vulnerability.Fixed in 1.23.11
Event History
Frequently Asked Questions
What is CVE-2023-35945?
CVE-2023-35945 is a vulnerability in Envoy's HTTP/2 codec that may leak a header map and bookkeeping structures.
What is the severity of CVE-2023-35945?
CVE-2023-35945 has a severity rating of 7.5 (High).
How does CVE-2023-35945 affect Envoy?
CVE-2023-35945 affects Envoy versions up to and including 1.26.3.
How can I fix CVE-2023-35945?
To fix CVE-2023-35945, upgrade to Envoy version 1.26.3 or apply the appropriate patch provided by Red Hat.
Where can I find more information about CVE-2023-35945?
You can find more information about CVE-2023-35945 in the references provided: [Ref 1](https://github.com/nghttp2/nghttp2/blob/e7f59406556c80904b81b593d38508591bb7523a/lib/nghttp2_session.c#L3346), [Ref 2](https://github.com/envoyproxy/envoy/security/advisories/GHSA-jfxv-29pc-x22r), [Ref 3](https://access.redhat.com/errata/RHSA-2023:4624)