TI-2025-05843 Aliases CVE-2025-6442 GHSA-r995-q44h-hr64

Ruby WEBrick read_header HTTP Request Smuggling Vulnerability

LOW 27CWE-444Published 2025-06-25 · Updated 2025-06-25

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: High
Impact type: —
Confidentiality · integrity · availability: None · High · None
Fix status: Partial Red Hat: 8 without a fix

Attack profile from CVSS 3.1 · NVD. Fix status from CNA, GitHub and Red Hat.

Summary

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. 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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00495 42nd percentileScored 2026-11-07

Fix Partial webrick (RubyGems): 1.8.2Red Hat: 8 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
ruby	WEBrick	1.8.1	—	No fix listed	CNA
—	webrick (RubyGems)	before 1.8.2	1.8.2	Patch available	GHSA-r995-q44h-hr64

WEBrick Vendorruby Affected 1.8.1 Fixed in — No fix listed CNA
webrick (RubyGems) Vendor— Affected before 1.8.2 Fixed in 1.8.2 Patch available GHSA-r995-q44h-hr64

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:ruby-lang:webrick::::::ruby::*	before 1.8.2	Vulnerable	ruby

cpe:2.3:a:ruby-lang:webrick:*:*:*:*:*:ruby:*:* Versions before 1.8.2 Vulnerable ·ruby

Remediation

Fix · GHSA-r995-q44h-hr64 webrick (RubyGems) Fixed in 1.8.2 Advisory →

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

Product	Status	Plan or fix
Logging Subsystem for Red Hat OpenShift	Affected	No fix yet: Fix deferred
OpenShift Service Mesh 3	Affected	No fix yet: Fix deferred
Red Hat 3scale API Management Platform 2	Affected	No fix yet: Fix deferred
Red Hat Enterprise Linux 6	Affected	No fix planned: Out of support scope
Red Hat Enterprise Linux 7	Affected	No fix planned: Out of support scope
Red Hat Enterprise Linux 8	Affected	No fix planned: Out of support scope
Red Hat Enterprise Linux 9	Affected	No fix yet: Fix deferred
Red Hat Satellite 6	Affected	No fix yet: Fix deferred

Not affected: 4 products

Red Hat Enterprise Linux 10
Red Hat Enterprise Linux 8
Red Hat Enterprise Linux 9
Red Hat OpenShift Container Platform 4

Timeline

2026-10-02 Threatist record created from CVE-2025-6442
2026-10-03 Alias added: GHSA-r995-q44h-hr64

References

Patch 1

vendor-provided URL

Advisory 2

Other 3

TI-2009-04253 WEBrick 1.3.1 in Ruby 1.8.6 through patchlevel 383, 1.8.7 through patchlevel 248… CVSS 2.0HIGH 7.5
TI-2008-01097 Directory traversal vulnerability in WEBrick in Ruby 1.8 before 1.8.5-p115 and… CVSS 2.0MEDIUM 5.0
TI-2020-15633 An issue was discovered in Ruby through 2.5.8, 2.6.x through 2.6.6, and 2.7.x through… CVSS 3.1HIGH 7.5
TI-2019-08907 The WEBrick gem 1.4.2 for Ruby allows directory traversal if the attacker once had local… CVSS 3.0MEDIUM 5.5

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences