Envoy up to 1.34.4/1.35.0 use after free

Summaryinfo

A vulnerability labeled as critical has been found in Envoy up to 1.34.4/1.35.0. Affected by this vulnerability is an unknown functionality. Executing a manipulation can lead to use after free. The identification of this vulnerability is CVE-2025-54588. The attack may be launched remotely. There is no exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in Envoy up to 1.34.4/1.35.0. It has been declared as critical. This vulnerability affects an unknown part. The manipulation with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. As an impact it is known to affect availability. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability was named CVE-2025-54588 since 07/25/2025. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. The technical details are unknown and an exploit is not available.

The vulnerability scanner Nessus provides a plugin with the ID 281808 (Amazon Linux 2 : ecs-service-connect-agent, --advisory ALAS2ECS-2025-093 (ALASECS-2025-093)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 1.34.5 or 1.35.1 eliminates this vulnerability. The upgrade is hosted for download at github.com.

The vulnerability is also documented in the databases at Tenable (281808) and CERT Bund (WID-SEC-2025-2085). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Affected

• Amazon Linux 2
• Red Hat OpenShift

Productinfo

Name

• Envoy

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.7
• 1.8
• 1.9
• 1.10
• 1.11
• 1.12
• 1.13
• 1.14
• 1.15
• 1.16
• 1.17
• 1.18
• 1.19
• 1.20
• 1.21
• 1.22
• 1.23
• 1.24
• 1.25
• 1.26
• 1.27
• 1.28
• 1.29
• 1.30
• 1.31
• 1.32
• 1.33
• 1.34
• 1.34.0
• 1.34.1
• 1.34.2
• 1.34.3
• 1.34.4
• 1.35.0

License

• free

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

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Entryinfo

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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