CVE-2024-49214Network attack vector

Unauthenticated allowlist bypass via missing 0-RTT address validation

Published Oct 14, 2024 · Updated Oct 29, 2024

Authentication bypass in HAProxy allows remote attackers to evade QUIC listener IP controls by resuming 0-RTT with a spoofed address. The QUIC listener accepts early HTTP/3 data during ticket resumption without requiring a token that validates the sender address, so a spoofed trusted address passes the IP allow/block list. Exploitation requires QUIC 0-RTT to be enabled and a session ticket obtained through an earlier connection from the attacker's real address; the result is access to HTTP/3 requests that the IP rules should reject.

CVSS severity5.3
Medium
EPSS probability0.52%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in HAProxy allows remote attackers to evade QUIC listener IP controls by resuming 0-RTT with a spoofed address. The QUIC listener accepts early HTTP/3 data during ticket resumption without requiring a token that validates the sender address, so a spoofed trusted address passes the IP allow/block list. Exploitation requires QUIC 0-RTT to be enabled and a session ticket obtained through an earlier connection from the attacker's real address; the result is access to HTTP/3 requests that the IP rules should reject.

The record

CVE
CVE-2024-49214
Published
Oct 14, 2024
Updated
Oct 29, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-290, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 14, 2024CVE publishedPublication date reported by the CVE source.
  2. Oct 29, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.3MITRECVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

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.

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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 exploitUnconfirmed

Weakness, pattern, technique

CWE-290Authentication Bypass by Spoofing
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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