Use-after-free in envoy - CVE-2026-73512
Published: August 26, 2026
Vulnerability identifier: #VU145871
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-73512
CWE-ID: CWE-416
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to use-after-free in the Envoy QUIC/HTTP/3 datagram handling logic when processing an HTTP/3 Datagram for a stream that has been recreated after an internal redirect or similar stream recreation event. A remote attacker can send a specially crafted HTTP/3 Datagram after stream recreation to cause a denial of service.
Exploitation requires HTTP/3 over QUIC with datagrams enabled, Capsule Protocol in use, and a request flow that triggers stream recreation such as an internal redirect.
Affected software
envoy
Istio
Istio
How to mitigate CVE-2026-73512
Install security update from vendor's website.
envoy - addressed in versions 1.36.10, 1.37.6, 1.38.4, 1.39.1
Istio - addressed in versions 1.29.7, 1.30.4
Istio - addressed in versions 1.29.7, 1.30.4