CVE-2025-24947Network attack vector

Server stall via colliding QUIC connection identifiers

Published Feb 20, 2025 · Updated Feb 20, 2025

Hash-collision DoS in LiteSpeed Technologies LSQUIC before 4.2.0 allows remote attackers to stall servers via crafted QUIC SCIDs. The connection-management table indexes attacker-chosen Source Connection IDs with XXH32, so colliding identifiers degrade insertion and lookup operations toward quadratic work. Unauthenticated clients need only initiate many parallel QUIC connections; affected servers can spend most CPU time processing collision chains and stop serving traffic.

CVSS severity5.3
Medium
EPSS probability0.68%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Hash-collision DoS in LiteSpeed Technologies LSQUIC before 4.2.0 allows remote attackers to stall servers via crafted QUIC SCIDs. The connection-management table indexes attacker-chosen Source Connection IDs with XXH32, so colliding identifiers degrade insertion and lookup operations toward quadratic work. Unauthenticated clients need only initiate many parallel QUIC connections; affected servers can spend most CPU time processing collision chains and stop serving traffic.

The record

CVE
CVE-2025-24947
Published
Feb 20, 2025
Updated
Feb 20, 2025
Vendor
LiteSpeed Technologies
Product
LSQUIC
Classifications
CWE-407, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 20, 2025CVE publishedPublication date reported by the CVE source.
  2. Feb 20, 2025Record 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=0 <4.2.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

LiteSpeed Technologies · LSQUICversion=0 <4.2.0

Published CVSS scores

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

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-407Inefficient Algorithmic Complexity
T1499.004Application or System Exploitation

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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