Vulnerability in Apache Httpclient

CVE-2025-27820

A bug in PSL validation logic in Apache HttpClient 5.4.x disables domain checks, affecting cookie management and host name verification. Discovered by the Apache HttpClient team. Fixed in the 5.4.3 release

Vulnerability class: Improper Certificate Validation

EPSS: 0.008 (52.2th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-27820?
CVE-2025-27820 is a high-severity vulnerability in Apache Httpclient, classified under Improper Certificate Validation. CVSS score: 7.5/10. Published 2025-04-24.
How severe is CVE-2025-27820?
High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2025-27820 known to be exploited?
4 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.