Is CVE-2025-54939 in the CISA KEV catalog?

No. CVE-2025-54939 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2025-54939?

CVE-2025-54939 has a CVSS v3 base score of 5.3 (MEDIUM).

What is the EPSS score for CVE-2025-54939?

CVE-2025-54939 has an EPSS score of 0.77% (51th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2025-54939?

Upgrade litespeed web adc to 3.3.1 or later. Fixes are available for 4 affected products.

CVE & CISA-KEV Catalog

CVE-2025-54939

MEDIUM

5.3

CVSS v3

NVD

Description

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

CWE-770Allocation of Resources Without Limits or Throttling CWE-401Missing Release of Memory (Memory Leak)

How to fix

Remediation Available

litespeed web adcNVD

Affected:< 3.3.1Fixed in:3.3.1CVE-2025-54939derived from NVD

litespeed web serverNVD

Affected:< 6.3.4Fixed in:6.3.4CVE-2025-54939derived from NVD

lsquicNVD

Affected:< 4.3.1Fixed in:4.3.1CVE-2025-54939derived from NVD

openlitespeedNVD

Affected:< 1.8.4Fixed in:1.8.4CVE-2025-54939derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityLow

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

Exploit Intelligence

0.77%probability of exploitation in 30 days

51stpercentile

Moderate risk: more likely to be exploited than 51% of all known CVEs.

References

Exploit1

imperva.com

Vendor Advisory1

blog.litespeedtech.com

Release Notes2

Related Vulnerabilities

Other CWE-770 (Allocation of Resources Without Limits or Throttling) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-50387	High	7.5	100%	-	Fix
CVE-2019-11478	Medium	5.3	95%	-	Fix
CVE-2019-11479	High	7.5	92%	-	Fix
CVE-2024-27316	High	7.5	91%	-	Fix
CVE-2022-30522	High	7.5	90%	-	Fix
CVE-2019-9515	High	7.5	88%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-08-27.