CVE-2026-73549

5.3 MEDIUMpublic exploit available

Published 2026-09-21 · Updated 2026-09-21

AI risk analysis

Summary: The flaw allows reconstruction of scoped IPv6 addresses leading to process termination in specific configurations; it matters because it can disrupt service availability.
Exploitability: Exploitation requires kernel-provided scoped IPv6 destinations or affected QUIC paths, making it moderately difficult.
Blast radius: If exploited, it could terminate processes handling original destination transparent-proxy deployments or QUIC connections, impacting service reliability.
Prioritized remediation: Update to Envoy versions 1.36.10, 1.37.6, 1.38.4, or 1.39.1 immediately.

proxyipv6process-terminationnetwork

Analysis generated locally by qwen2.5:7b-instruct (no data left the box). AI-assisted — verify against primary sources before acting.

NVD description

Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.36.10, 1.37.6, 1.38.4, and 1.39.1, Envoy's Utility::copyInternetAddressAndPort and QUIC client-address paths reconstruct scoped IPv6 addresses through addressAsString and Ipv6Instance. The string includes a percent scope identifier that inet_pton cannot parse, causing an exception or abort. Kernel-provided scoped IPv6 destinations in ORIGINAL_DST transparent-proxy deployments, and affected QUIC connection paths, can therefore terminate the process. The relevant scope boundary is that the HTTP use_http_header override rejects scoped addresses earlier; the advisory's crash path requires a kernel-provided original destination or the affected QUIC path. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

Weaknesses

CWE-754

Public exploit & PoC references

All references

Source data: NVD (nvd.nist.gov), public domain. Exploit-DB.ai adds local AI analysis for defensive use only.

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