Cyber Resilience

CVE-2025-6442

Medium

Published: 25 June 2025

Published
25 June 2025
Modified
18 August 2025
KEV Added
Patch
CVSS Score v3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
EPSS Score 0.0026 49.4th percentile
Risk Priority 12 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-6442 is a medium-severity HTTP Request/Response Smuggling (CWE-444) vulnerability in Ruby-Lang Webrick. Its CVSS base score is 5.9 (Medium).

Operationally, ranked at the 49.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

Ruby WEBrick read_header HTTP Request Smuggling Vulnerability. This vulnerability allows remote attackers to smuggle arbitrary HTTP requests on affected installations of Ruby WEBrick. This issue is exploitable when the product is deployed behind an HTTP proxy that fulfills specific conditions.…

more

The specific flaw exists within the read_headers method. The issue results from the inconsistent parsing of terminators of HTTP headers. An attacker can leverage this vulnerability to smuggle arbitrary HTTP requests. Was ZDI-CAN-21876.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

ruby-lang
webrick
≤ 1.8.2

Mitigating Controls

No mitigating controls mapped yet. The per-CVE control annotator has not reached this CVE.

References