CVE-2024-32975Public exploitNetwork attack vector

Proxy crash via QUIC receive-buffer underflow

Published Jun 4, 2024 · Updated Aug 2, 2024

Denial of service in Envoy before 1.30.2 allows remote attackers to crash the proxy with crafted HTTP/3 traffic. QuicStreamSequencerBuffer::PeekRegion subtracts a higher circular-buffer start offset from a lower end offset after heavy buffering, underflowing the peek length passed to QuicheDataReader::PeekVarInt62Length. Exposure requires an HTTP/3 upstream or downstream and a blocked QPACK stream near the 64 MB receive-buffer wrap point; the resulting invalid read terminates Envoy.

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

Denial of service in Envoy before 1.30.2 allows remote attackers to crash the proxy with crafted HTTP/3 traffic. QuicStreamSequencerBuffer::PeekRegion subtracts a higher circular-buffer start offset from a lower end offset after heavy buffering, underflowing the peek length passed to QuicheDataReader::PeekVarInt62Length. Exposure requires an HTTP/3 upstream or downstream and a blocked QPACK stream near the 64 MB receive-buffer wrap point; the resulting invalid read terminates Envoy.

The record

CVE
CVE-2024-32975
Published
Jun 4, 2024
Updated
Aug 2, 2024
Vendor
Envoy Proxy
Product
Envoy
Classifications
CWE-191, 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=0 <=1.27.5
  2. Affected versionversion=<= 1.27.5
  3. Affected versionversion=>= 1.28.0, <= 1.28.3
  4. Affected versionversion=1.28.0 <=1.28.3
  5. Affected versionversion=>= 1.29.0, <= 1.29.4
  6. Affected versionversion=1.29.0 <=1.29.4
  7. Affected versionversion=>= 1.30.0, <= 11.30.1
  8. Affected versionversion=1.30.0 <=1.30.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Envoy Proxy · Envoyversion=0 <=1.27.5; version=<= 1.27.5; version=>= 1.28.0, <= 1.28.3; version=1.28.0 <=1.28.3; version=>= 1.29.0, <= 1.29.4; version=1.29.0 <=1.29.4; version=>= 1.30.0, <= 11.30.1; version=1.30.0 <=1.30.1

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
7.5NIST NVDCVSS: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.

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-191Integer Underflow (Wrap or Wraparound)
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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Your stack

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