How severe is CVE-2023-53878?

CVE-2023-53878 has a CVSS 4.0 base score of 6.9, rated medium severity.

Is CVE-2023-53878 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2023-53878?

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

Does CVE-2023-53878 have an EU (EUVD) identifier?

Yes. CVE-2023-53878 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-203431.

When was CVE-2023-53878 published?

CVE-2023-53878 was published on 2025-12-15 and last updated on 2026-06-17.

CVE-2023-53878

CVE-2023-53878 is a medium-severity vulnerability with a CVSS 4.0 base score of 6.9. 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-444.

Key facts

Severity: Medium (CVSS 4.0 base score 6.9)
EPSS exploit prediction: 0% (23rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-203431
Weakness: CWE-444
Published: 2025-12-15
Last modified: 2026-06-17

Description

Member Login Script 3.3 contains a client-side desynchronization vulnerability that allows attackers to manipulate HTTP request handling by exploiting Content-Length header parsing. Attackers can send crafted POST requests with smuggled secondary requests to potentially bypass server-side request processing controls.

Frequently asked questions

What is CVE-2023-53878?: Member Login Script 3.3 contains a client-side desynchronization vulnerability that allows attackers to manipulate HTTP request handling by exploiting Content-Length header parsing. Attackers can send crafted POST requests with smuggled secondary requests to potentially bypass server-side request processing controls.
How severe is CVE-2023-53878?: CVE-2023-53878 has a CVSS 4.0 base score of 6.9, rated medium severity.
Is CVE-2023-53878 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2023-53878?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2023-53878 have an EU (EUVD) identifier?: Yes. CVE-2023-53878 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-203431.
When was CVE-2023-53878 published?: CVE-2023-53878 was published on 2025-12-15 and last updated on 2026-06-17.

References

Other CWE-444 (HTTP Request/Response Smuggling) vulnerabilities

CVE-2025-1867 — Critical (CVSS 10.0): Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in ithewei libhv allows…
CVE-2022-22536 — Critical (CVSS 10.0): SAP NetWeaver Application Server ABAP, SAP NetWeaver Application Server Java, ABAP Platform, SAP Content Server 7.53…
CVE-2018-3907 — Critical (CVSS 10.0): An exploitable vulnerability exists in the REST parser of video-core's HTTP server of the Samsung SmartThings Hub…
CVE-2025-55315 — Critical (CVSS 9.9): Inconsistent interpretation of http requests ('http request/response smuggling') in ASP.NET Core allows an authorized…
CVE-2020-15049 — Critical (CVSS 9.9): An issue was discovered in http/ContentLengthInterpreter.cc in Squid before 4.12 and 5.x before 5.0.3. A Request…
CVE-2026-13763 — Critical (CVSS 9.8): Inconsistent interpretation of HTTP/2 requests in AWS Application Load Balancer with AWS WAF enabled might allow remote…

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