CVE-2025-54939Public exploitNetwork attack vector

Pre-handshake service crash via leaked packet allocations

Published Aug 1, 2025 · Updated Aug 20, 2025

Memory exhaustion in LiteSpeed Technologies LSQUIC before 4.3.1 allows remote attackers to crash QUIC servers with crafted UDP datagrams. In lsquic_engine_packet_in, the coalesced-packet path retains packet_in structures for packets whose destination connection IDs fail validation instead of returning them through lsquic_mm_put_packet_in. Repeated pre-handshake datagrams cause linear memory growth until the exposed process becomes unresponsive or is terminated for exhausting memory.

CVSS severity5.3
Medium
EPSS probability0.77%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Memory exhaustion in LiteSpeed Technologies LSQUIC before 4.3.1 allows remote attackers to crash QUIC servers with crafted UDP datagrams. In lsquic_engine_packet_in, the coalesced-packet path retains packet_in structures for packets whose destination connection IDs fail validation instead of returning them through lsquic_mm_put_packet_in. Repeated pre-handshake datagrams cause linear memory growth until the exposed process becomes unresponsive or is terminated for exhausting memory.

The record

CVE
CVE-2025-54939
Published
Aug 1, 2025
Updated
Aug 20, 2025
Vendor
LiteSpeed Technologies
Product
LSQUIC
Classifications
CWE-770, CWE-401, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 1, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 20, 2025Record 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 <4.3.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

LiteSpeed Technologies · LSQUICversion=0 <4.3.1

Published CVSS scores

7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.3MITRE CNACVSS: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.

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-770Allocation of Resources Without Limits or Throttling
CWE-401Missing Release of Memory after Effective Lifetime
T1499Endpoint Denial of Service

Public exploit references

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

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo