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CVE-2025-6442

18
FAUCET Score

CVE-2025-6442 describes an HTTP Request Smuggling vulnerability in Ruby WEBrick, specifically within the read_headers method, due to inconsistent parsing of HTTP header terminators. This flaw allows remote attackers to smuggle arbitrary HTTP requests when WEBrick is deployed behind a susceptible HTTP proxy. The vulnerability is rated Medium severity (CVSS 5.9) with a network attack vector and high impact to integrity, but requires high attack complexity. Currently, there is no evidence of active exploitation, public exploit code, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
< 1.8.2CPE matchmatch criteria
cpe:2.3:a:ruby-lang:webrick:*:*:*:*:*:ruby:*:*

CVSS Data

CVSS version used by this source: 3.0

6.5MEDIUM

CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N

Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
LOW
Integrity Impact
HIGH
Availability Impact
NONE
Exploitability Score
2.2
Impact Score
4.2
CvssVersion
3.0

Exploit Intelligence

EPSS Score
0.42%
Probability of exploitation in next 30 days
EPSS Percentile
34.6%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0042 is in the 4th percentile among its peer group of 19,955 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.0 Bluesky, 0.0 Mastodon, and 0.2 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (33)

github_advisorypatch availablevia nvd_reference
View patch
microsoftpatch availablevia msrc
Product: azl3 ruby 3.3.5-4 on Azure Linux 3.0Fixed in: 3.3.5-4
microsoftpatch availablevia msrc
Product: 20198-17084Fixed in: 1.8.1-2
microsoftpatch availablevia msrc
Product: 20201-17086Fixed in: 3.1.7-2
microsoftpatch availablevia msrc
Product: 20208-17086Fixed in: 1.7.0-2
microsoftpatch availablevia msrc
Product: 20193-17084Fixed in: 3.3.5-4
microsoftpatch availablevia msrc
Product: CBL Mariner 2.0 x64Fixed in: 3.1.7-2
microsoftpatch availablevia msrc
Product: CBL Mariner 2.0 x64Fixed in: 1.7.0-2
microsoftpatch availablevia msrc
Product: CBL Mariner 2.0 ARMFixed in: 3.1.7-2
microsoftpatch availablevia msrc
Product: CBL Mariner 2.0 ARMFixed in: 1.7.0-2
microsoftpatch availablevia msrc
Product: Azure Linux 3.0 x64Fixed in: 3.3.5-4
microsoftpatch availablevia msrc
Product: Azure Linux 3.0 x64Fixed in: 1.8.1-2
microsoftpatch availablevia msrc
Product: Azure Linux 3.0 ARMFixed in: 3.3.5-4
microsoftpatch availablevia msrc
Product: Azure Linux 3.0 ARMFixed in: 1.8.1-2
microsoftpatch availablevia msrc
Product: azl3 rubygem-webrick 1.8.1-2 on Azure Linux 3.0Fixed in: 1.8.1-2
microsoftpatch availablevia msrc
Product: cbl2 ruby 3.1.7-1 on CBL Mariner 2.0Fixed in: 3.1.7-2
microsoftpatch availablevia msrc
Product: cbl2 rubygem-webrick 1.7.0-2 on CBL Mariner 2.0Fixed in: 1.7.0-2
rubygemspatch availablevia ghsa
Product: webrickFixed in: 1.8.2
redhatvendor investigatingvia redhat_api
Product: Logging Subsystem for Red Hat OpenShiftFixed in: openshift-logging/fluentd-rhel9
redhatvendor investigatingvia redhat_api
Product: Logging Subsystem for Red Hat OpenShiftFixed in: openshift-logging/fluentd-rhel8
redhatvendor investigatingvia redhat_api
Product: OpenShift Service Mesh 3Fixed in: openshift-service-mesh-dev-preview-beta/istio-ztunnel-rhel9
redhatvendor investigatingvia redhat_api
Product: OpenShift Service Mesh 3Fixed in: openshift-service-mesh/istio-cni-rhel9
redhatvendor investigatingvia redhat_api
Product: OpenShift Service Mesh 3Fixed in: openshift-service-mesh/istio-must-gather-rhel9
redhatvendor investigatingvia redhat_api
Product: OpenShift Service Mesh 3Fixed in: openshift-service-mesh/istio-pilot-rhel9
redhatvendor investigatingvia redhat_api
Product: OpenShift Service Mesh 3Fixed in: openshift-service-mesh/istio-proxyv2-rhel9
redhatvendor investigatingvia redhat_api
Product: OpenShift Service Mesh 3Fixed in: openshift-service-mesh/istio-rhel9-operator
redhatvendor investigatingvia redhat_api
Product: OpenShift Service Mesh 3Fixed in: openshift-service-mesh/istio-sail-operator-bundle
redhatvendor investigatingvia redhat_api
Product: Red Hat 3scale API Management Platform 2Fixed in: 3scale-amp2/zync-rhel8
redhatvendor investigatingvia redhat_api
Product: Red Hat 3scale API Management Platform 2Fixed in: 3scale-amp2/zync-rhel9
redhatvendor investigatingvia redhat_api
Product: Red Hat Enterprise Linux 9Fixed in: pcs
redhatvendor investigatingvia redhat_api
Product: Red Hat Satellite 6Fixed in: puppet-agent
redhatvendor investigatingvia redhat_api
Product: Red Hat Satellite 6Fixed in: rubygem-webrick
redhatvendor investigatingvia redhat_api
Product: Red Hat Satellite 6Fixed in: satellite:el8/rubygem-webrick

Vendor Advisories (3)

rubygemsGHSA-r995-q44h-hr64medium

Ruby WEBrick read_headers method can lead to HTTP Request/Response Smuggling

Jun 26, 2025
redhatCVE-2025-6442Moderate

webrick: Ruby WEBrick Request Smuggling Vulnerability

Jun 25, 2025
microsoft2025-Jun/CVE-2025-6442

Ruby WEBrick read_header HTTP Request Smuggling Vulnerability

Jun 10, 2025

References

github.com / ruby/webrick/commit/ee60354bcb84ec33b9245e1d1aa6e1f7e8132101
Patch
zerodayinitiative.com / advisories/ZDI-25-414
Third Party Advisory