LiteSpeed QUIC (LSQUIC) Library before 4.3.1 has an lsquic_engine_packet_in memory leak.

published 2025-08-01 15 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-23337

cvss: 5.3; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.8%; EPSS 0.8% chance of exploitation in 30 days, percentile 58%
public exploits: 0; none known

Patch / fix

fixed in 1 links 1

litespeedtech LSQUIC 4.3.1

github.com/litespeedtech/lsquic@4cd9252 commit

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 15 mo ago (2025-08-01)

Exploit prediction

0.84% chance of exploitation in the next 30 days, higher than 58% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

imperva.com https://www.imperva.com/blog/quic-leak-cve-2025-54939-new-high-risk-pre-handshake-remote-denial-of-service-in-lsquic-quic-implementation/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	3.1	5.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
NVD	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

litespeedtech LSQUIC

Classification

Weakness

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

References

github.com /litespeedtech/lsquic/commit/4cd9252e77fb4a36b572e2167a84067d603d3b23
release-notes
imperva.com /blog/quic-leak-cve-2025-54939-new-high-risk-pre-handshake-remote-denial-of-service-in-lsquic-quic-implementat
exploit, third-party-advisory
blog.litespeedtech.com /2025/08/18/litespeed-security-update/
vendor-advisory
github.com /litespeedtech/lsquic/blob/70486141724f85e97b08f510673e29f399bbae8f/CHANGELOG#L1-L3
release-notes

Sources

CVE List CVE-2025-54939
NVD CVE-2025-54939

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary