CVE-2024-32974Public exploitNetwork attack vector

Unauthenticated proxy crash via delayed QPACK headers

Published Jun 4, 2024 · Updated Aug 2, 2024

Use-after-free in Envoy before 1.30.2 allows remote attackers to crash the proxy through a crafted HTTP/3 request sequence. EnvoyQuicServerStream::OnInitialHeadersComplete accesses a destroyed HCM ActiveStream after STOP_SENDING stops reads but QUICHE later completes delayed QPACK header decoding. The service must expose a downstream HTTP/3 listener, and successful exploitation terminates the Envoy process without reported data disclosure or modification.

CVSS severity5.9
Medium
EPSS probability0.69%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Envoy before 1.30.2 allows remote attackers to crash the proxy through a crafted HTTP/3 request sequence. EnvoyQuicServerStream::OnInitialHeadersComplete accesses a destroyed HCM ActiveStream after STOP_SENDING stops reads but QUICHE later completes delayed QPACK header decoding. The service must expose a downstream HTTP/3 listener, and successful exploitation terminates the Envoy process without reported data disclosure or modification.

The record

CVE
CVE-2024-32974
Published
Jun 4, 2024
Updated
Aug 2, 2024
Vendor
Envoy Proxy
Product
Envoy
Classifications
CWE-416, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 4, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 2024Record 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=<= 1.27.5
  2. Affected versionversion=>= 1.28.0, <= 1.28.3
  3. Affected versionversion=>= 1.29.0, <= 1.29.4
  4. Affected versionversion=>= 1.30.0, <= 11.30.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Envoy Proxy · Envoyversion=<= 1.27.5; version=>= 1.28.0, <= 1.28.3; version=>= 1.29.0, <= 1.29.4; version=>= 1.30.0, <= 11.30.1

Published CVSS scores

5.9GitHub, Inc.CVSS:3.1/AV:N/AC:H/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.

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

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-416Use After Free
T1499.004Application 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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Your stack

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