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Fencer Vulns
high 7.5

CVE-2025-54588 json

Envoy: Race condition in Dynamic Forward Proxy leads to use-after-free and segmentation faults

published 2025-09-02 14 mo ago modified 2026-09-08 2 mo ago also BIT-envoy-2025-54588 , EUVD-2025-26470 , GHSA-g9vw-6pvx-7gmw

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 42%
public exploits
0
none known

Summary

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.

Patch / fix

  • go github.com/envoyproxy/envoy 1.34.5, 1.35.1
  • bitnami envoy 1.34.5, 1.35.1
  • envoyproxy envoy 1.34.5, 1.35.1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-54588 updated cvss 7.5

envoyproxy/envoy: Use after free in DNS cache

  • Red Hat OpenShift Service Mesh 3.0 openshift-service-mesh 1.24.6-1757566151
    fixed: vendor fix RHSA-2025:16040
  • Red Hat OpenShift Service Mesh 3.1 openshift-service-mesh 1.26.4-1757524855
    fixed: vendor fix RHSA-2025:16044
  • Red Hat OpenShift Service Mesh 3 openshift-service-mesh/istio-cni-rhel9, openshift-service-mesh/istio-pilot-rhel9, openshift-service-mesh/istio-rhel9-operator, openshift-service-mesh/istio-must-gather-rhel9, openshift-service-mesh/istio-sail-operator-bundle, openshift-service-mesh-tech-preview/istio-ztunnel-rhel9, +1 more
    not affected: component not present
  • Red Hat OpenShift Service Mesh 3.0 openshift-service-mesh 3.0.4-1757399855, openshift-service-mesh 3.0.5-1757344982, openshift-service-mesh 3.0.5-1757571023, openshift-service-mesh 1.24.6-1757501978, openshift-service-mesh 1.24.6-1757501992, openshift-service-mesh-dev-preview-beta 1.24.6-1757400466 Red Hat OpenShift Service Mesh 3.1 openshift-service-mesh 3.1.1-1757004529, openshift-service-mesh 3.1.2-1757494706, openshift-service-mesh 3.1.2-1757594700, openshift-service-mesh 1.26.4-1757491204, openshift-service-mesh 1.26.4-1757588670, openshift-service-mesh-tech-preview 1.26.4-1757504327
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
14 mo ago

Exploit prediction

0.50% chance of exploitation in the next 30 days, higher than 42% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
go github.com/envoyproxy/envoy
>=1.35.0, <1.35.1
>=1.34.0, <1.34.5
1.35.1
1.34.5
bitnami envoy
>=1.34.0, <1.34.5
>=1.35.0, <1.35.1
1.34.5
1.35.1

Affected products

  • envoyproxy envoy

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.