CVE-2026-73513Public exploitNetwork attack vectorHinoki check available

Proxy crash via unterminated oghttp2 response trailers

Published Sep 21, 2026 · Updated Sep 21, 2026

Use-after-free in Envoy before 1.36.10, 1.37.0 through 1.37.5, 1.38.0 through 1.38.3, and 1.39.0 allows remote attackers to crash it. The oghttp2 client codec accepts response trailer HEADERS without END_STREAM, so ActiveRequest is deleted while ClientStreamImpl retains a dangling response_decoder_ reference that a later frame invokes. Exploitation requires control of an upstream HTTP/2 peer and the optional oghttp2 codec; the default nghttp2 codec rejects the malformed trailers, limiting the consequence to a proxy-process crash.

CVSS severity7.5
High
EPSS probability0.48%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Use-after-free in Envoy before 1.36.10, 1.37.0 through 1.37.5, 1.38.0 through 1.38.3, and 1.39.0 allows remote attackers to crash it. The oghttp2 client codec accepts response trailer HEADERS without END_STREAM, so ActiveRequest is deleted while ClientStreamImpl retains a dangling response_decoder_ reference that a later frame invokes. Exploitation requires control of an upstream HTTP/2 peer and the optional oghttp2 codec; the default nghttp2 codec rejects the malformed trailers, limiting the consequence to a proxy-process crash.

The record

CVE
CVE-2026-73513
Published
Sep 21, 2026
Updated
Sep 21, 2026
Vendor
Envoy Proxy
Product
Envoy
Classifications
CWE-20, CWE-416, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 21, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.36.10
  2. Affected versionversion=>= 1.37.0, < 1.37.6
  3. Affected versionversion=>= 1.38.0, < 1.38.4
  4. Affected versionversion=>= 1.39.0, < 1.39.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Envoy Proxy · Envoyversion=< 1.36.10; version=>= 1.37.0, < 1.37.6; version=>= 1.38.0, < 1.38.4; version=>= 1.39.0, < 1.39.1

Published CVSS scores

7.5Envoy Proxy GitHub Security AdvisoryCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5Amazon LinuxCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-20Improper Input Validation
CWE-416Use After Free
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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