Use After Free in Envoyproxy Envoy

CVE-2026-73513

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 optional oghttp2 upstream HTTP/2 codec accepts a response trailer HEADERS frame without END_STREAM. Envoy completes and deferred-deletes the ActiveRequest while oghttp2 keeps the stream open, leaving ClientStreamImpl with a dangling response_decoder_ reference. A later frame on the stream can dispatch through the freed object and crash the process. The relevant scope boundary is that the default nghttp2 codec rejects the malformed trailers, and the trigger is upstream-only with oghttp2 enabled. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.

Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.005 (42.4th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 42nd percentile — 42.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-73513: held from 0.005 to 0.005.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: +0.000

Affected products

  • Envoyproxy Envoy — versions < 1.36.10, >= 1.37.0, < 1.37.6, >= 1.38.0, < 1.38.4

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-73513?
CVE-2026-73513 is a high-severity vulnerability in Envoyproxy Envoy, classified under Improper Input Validation. CVSS score: 7.5/10. Published 2026-09-21.
How severe is CVE-2026-73513?
High severity. CVSS v3 base score is 7.5 out of 10.