Cyber Resilience

CVE-2025-54588

Memory Safety in Envoyproxy Envoy 1.34.0 – 1.34.5

Published
03 September 2025
Modified
17 June 2026
Patch / advisory
CVSS Score v3.1 7.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0044 36th percentile
Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2025-54588 is a high-severity Use After Free (CWE-416) vulnerability in Envoyproxy Envoy. Its CVSS base score is 7.5 (High).

Operationally, ranked at the 36th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to CM-6 (Configuration Settings) and SI-16 (Memory Protection) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

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…

more

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.

CWE(s)

Related Threats

CVEs Like This One

CVE-2026-26330Same product: Envoyproxy Envoy
CVE-2026-26311Same product: Envoyproxy Envoy
CVE-2026-48090Same product: Envoyproxy Envoy
CVE-2024-32974Same product: Envoyproxy Envoy
CVE-2024-39305Same product: Envoyproxy Envoy
CVE-2026-47207Same product: Envoyproxy Envoy
CVE-2024-23322Same product: Envoyproxy Envoy
CVE-2026-47205Same product: Envoyproxy Envoy
CVE-2023-35942Same product: Envoyproxy Envoy
CVE-2023-35943Same product: Envoyproxy Envoy

Affected Assets

envoyproxy
envoy
1.35.0 · 1.34.0 — 1.34.5

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • SI-16 Memory Protection
  • SI-2 Flaw Remediation
  • CM-6 Configuration Settings
Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 3 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V1.4.3

Mitigating Controls (NIST 800-53 r5) AI

prevent

Directly implements memory safety protections that block use-after-free exploitation in the Envoy DNS cache.

prevent

Requires prompt application of the vendor patches (1.34.5/1.35.1) that eliminate the UAF condition.

prevent

Enforces the documented runtime-flag setting (envoy.reloadable_features.dfp_cluster_resolves_hosts=false) that disables the vulnerable code path.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly incorporate memory-safety tooling and reviews that prevent most use-after-free defects.

ID.RA-01 partial match
prevents

Vulnerability identification processes can discover use-after-free issues via scanning or analysis but do not prevent their introduction.

PR.PS-02 partial match
prevents

Routine patching removes known use-after-free instances after they have been introduced in released software.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

detects

Security testing in development can detect use-after-free bugs before release.

prevents

Secure SDLC mandates memory-safety practices that reduce use-after-free defects.

prevents

Application security requirements can specify memory-management rules that mitigate use-after-free.

prevents

Secure architecture principles include memory-safety design choices that limit use-after-free exposure.

prevents

Secure coding standards directly prescribe avoidance of use-after-free patterns.

prevents

Change-management processes help ensure memory-safety fixes are deployed consistently.

References