What is CVE-2025-54588?

CVE-2025-54588 is a high-severity vulnerability in Envoyproxy Envoy, classified under Use After Free. CVSS score: 7.5/10. Published 2025-09-03.

How severe is CVE-2025-54588?

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

Is CVE-2025-54588 known to be exploited?

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

Use After Free in Envoyproxy Envoy

CVE-2025-54588

Envoy is an open source L7 proxy and communication bus designed for large modern service oriented architectures. Versions 1.34.0 through 1.34.4 and 1.35.0 contain a use-after-free (UAF) vulnerability in the DNS cache, causing abnormal process termination. The vulnerability is in Envoy's Dynamic Forward Proxy implementation, occurring when a completion callback for a DNS resolution triggers new DNS resolutions or removes existing pending resolutions. This condition may occur when the following conditions are met: dynamic Forwarding Filter is enabled, the `envoy.reloadable_features.dfp_cluster_resolves_hosts` runtime flag is enabled, and the Host header is modified between the Dynamic Forwarding Filter and Router filters. This issue is resolved in versions 1.34.5 and 1.35.1. To work around this issue, set the envoy.reloadable_features.dfp_cluster_resolves_hosts runtime flag to false.

Vulnerability class: Use-After-Free

Published 2025-09-03 · 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: 0.005 (38.9th percentile), scored 2026-10-05.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 39th percentile — 38.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000

Affected products

Envoyproxy Envoy — versions >= 1.34.0, < 1.34.5, >= 1.35.0, < 1.35.1, 1.35.0

Weakness classification (CWE)

CWE-416 — Use After Free

Public proof-of-concept exploits

fkie-cad/nvd-json-data-feeds

References

github.com/envoyproxy/envoy/security/advisories/GHSA-g9vw-6pvx-7gmw (Patch, Vendor Advisory)
github.com/envoyproxy/envoy/releases/tag/v1.34.5 (Release Notes)
github.com/envoyproxy/envoy/releases/tag/v1.35.1 (Release Notes)

Frequently asked questions

What is CVE-2025-54588?: CVE-2025-54588 is a high-severity vulnerability in Envoyproxy Envoy, classified under Use After Free. CVSS score: 7.5/10. Published 2025-09-03.
How severe is CVE-2025-54588?: High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2025-54588 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.