What is CVE-2023-35945?

CVE-2023-35945 is a high-severity vulnerability in Envoyproxy Envoy, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2023-07-13.

How severe is CVE-2023-35945?

High severity. CVSS v3 base score is 7.5 out of 10.

Is CVE-2023-35945 known to be exploited?

2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Resource exhaustion in Envoyproxy Envoy

CVE-2023-35945

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 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.

Vulnerability class: DoS (Denial of Service)

Published 2023-07-13 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.013 (69.0th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 69th percentile — 69.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.013 · newest: 0.013 · change: 0.000

Affected products

Envoyproxy Envoy — versions >= 1.26.0, < 1.26.3, >= 1.25.0, < 1.25.8, >= 1.24.0, < 1.24.9
Nghttp2

Weakness classification (CWE)

Public proof-of-concept exploits

References

github.com/envoyproxy/envoy/security/advisories/GHSA-jfxv-29pc-x22r (Vendor Advisory)
github.com/nghttp2/nghttp2/blob/e7f59406556c80904b81b593d38508591bb7523a/lib/ng… (Product)

Frequently asked questions

What is CVE-2023-35945?: CVE-2023-35945 is a high-severity vulnerability in Envoyproxy Envoy, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2023-07-13.
How severe is CVE-2023-35945?: High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2023-35945 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.