How severe is CVE-2025-54939?

CVE-2025-54939 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.

Is CVE-2025-54939 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (51st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-54939?

CVE-2025-54939 primarily affects Litespeedtech Litespeed Web Adc. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2025-54939?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2025-54939 have an EU (EUVD) identifier?

Yes. CVE-2025-54939 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-23337.

When was CVE-2025-54939 published?

CVE-2025-54939 was published on 2025-08-01 and last updated on 2026-06-17.

CVE-2025-54939

CVE-2025-54939 is a medium-severity vulnerability in Litespeedtech Litespeed Web Adc with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-401.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
EPSS exploit prediction: 1% (51st percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-23337
Weakness: CWE-401
Affected product: Litespeedtech Litespeed Web Adc
Published: 2025-08-01
Last modified: 2026-06-17

Description

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

Frequently asked questions

What is CVE-2025-54939?: LiteSpeed QUIC (LSQUIC) Library before 4.3.1 has an lsquic_engine_packet_in memory leak.
How severe is CVE-2025-54939?: CVE-2025-54939 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.
Is CVE-2025-54939 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (51st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-54939?: CVE-2025-54939 primarily affects Litespeedtech Litespeed Web Adc. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2025-54939?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-54939 have an EU (EUVD) identifier?: Yes. CVE-2025-54939 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-23337.
When was CVE-2025-54939 published?: CVE-2025-54939 was published on 2025-08-01 and last updated on 2026-06-17.

References

Affected products (4)

cpe:2.3:a:litespeedtech:litespeed_web_adc:*:*:*:*:*:*:*:*
cpe:2.3:a:litespeedtech:litespeed_web_server:*:*:*:*:*:*:*:*
cpe:2.3:a:litespeedtech:lsquic:*:*:*:*:*:*:*:*
cpe:2.3:a:litespeedtech:openlitespeed:*:*:*:*:*:*:*:*

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