Vulnerabilities in pkg:gem/webrick

PACKAGE
Advisory Identifier: GHSA-r995-q44h-hr64
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Advisory Summary

CVE-2025-6442 is a MODERATE (CVSS 6.5) ruby webrick read_headers method can vulnerability (CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')) affecting Webrick libraries in the RubyGems ecosystem. The issue involves ruby webrick read_headers method can lead to http request/response smuggling. Remediation is available by upgrading affected packages to version 1.8.2.

6 Known Advisory Record(s)
Package Vulnerability Intelligence

pkg:gem/webrick

6 Known Advisory Record(s)

Vulnerability advisories affecting package pkg:gem/webrick. Select an advisory below to view technical details or fixes.

Advisory ID CVE / NVD Severity Summary
GHSA-r995-q44h-hr64 CVE-2025-6442 MODERATE Ruby WEBrick read_headers method can lead to HTTP Request/Response Smuggling
GHSA-gwfg-cqmg-cf8f CVE-2020-25613 HIGH WEBRick vulnerable to HTTP Request/Response Smuggling
GHSA-6mq2-37j5-w6r6 CVE-2009-4492 MODERATE WEBrick Improper Input Validation vulnerability
GHSA-6f62-3596-g6w7 CVE-2024-47220 HIGH HTTP Request Smuggling in ruby webrick
GHSA-wfrc-r6c6-7j9r CVE-2008-4310 HIGH WEBrick Denial of Service Vulnerability
GHSA-369m-2gv6-mw28 CVE-2017-10784 HIGH WEBrick RCE Vulnerability

CVE-2025-6442 at a Glance

CVE Identifier CVE-2025-6442
GHSA Identifier GHSA-r995-q44h-hr64
Severity MODERATE
CVSS v3.1 Base Score 6.5
CWE Classification CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
Affected Product Webrick
Package Ecosystem RubyGems
Published Date
Last Updated

Security Impact

CVSS: 6.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N).

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality Low (C:L)
Integrity High (I:H)
Availability None (A:N)

How to Fix CVE-2025-6442

To remediate this vulnerability, upgrade all affected Webrick dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

webrick fixed: 1.8.2 
Upgrade webrick to 1.8.2
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for webrick

How to Check if You Are Affected

To determine whether your application is affected by CVE-2025-6442, inspect your project dependencies for Webrick:

inspect dependencies for webrick

Analyze the terminal output to locate any version of Webrick in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.8.2), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling'), where the product acts as an intermediary http agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed http requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination. In Webrick, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

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.

CVE-2025-6442 Affected Webrick Versions

1 component(s)
Fixed Versions:
1.8.2
Product / Package Ecosystem Affected Versions Fixed Version
webrick
gem/webrick
RubyGems
< 1.8.2
1.8.2

References

NVD — CVE-2025-6442 NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-6442
Security Fix Commit FIX COMMIT
https://github.com/ruby/webrick/commit/ee60354bcb84ec33b9245e1d1aa6e1f7e8132101#diff-ad02984d873efb089aa51551bc6b7d307a53e0ba1ac439e91d69c2e58a478864
Webrick Source Repository REPOSITORY
https://github.com/ruby/webrick
Webrick Source Repository REPOSITORY
https://github.com/rubysec/ruby-advisory-db/blob/master/gems/webrick/CVE-2025-6442.yml
www.zerodayinitiative.com/advisories/zdi-25-4... WEB
https://www.zerodayinitiative.com/advisories/ZDI-25-414

Frequently Asked Questions

What is CVE-2025-6442?
CVE-2025-6442 is a security vulnerability in Webrick involving Ruby WEBrick read_headers method can lead to HTTP Request/Response Smuggling under CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling').
Which Webrick versions are affected?
Affected versions include releases prior to 1.8.2 across affected packages: webrick.
What version fixes CVE-2025-6442?
Upgrading to 1.8.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is webrick affected?
Yes, webrick is affected in releases prior to 1.8.2. Upgrade your dependency to 1.8.2 or later.
What is the CVSS score of CVE-2025-6442?
CVE-2025-6442 has a CVSS v3.1 base score of 6.5 (MODERATE) with vector string CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N.
What CWE is associated with CVE-2025-6442?
CVE-2025-6442 is classified under CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') (The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.).
How can I check RubyGems dependencies for CVE-2025-6442?
Run the dependency tree command: 'inspect dependencies for webrick'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-r995-q44h-hr64",
  "modified" : "2025-06-30T12:53:53Z",
  "published" : "2025-06-26T21:31:13Z",
  "aliases" : [ "CVE-2025-6442" ],
  "summary" : "Ruby WEBrick read_headers method can lead to HTTP Request/Response Smuggling",
  "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.\n\nThe 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.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "RubyGems",
      "name" : "webrick"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.8.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-6442"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/ruby/webrick/commit/ee60354bcb84ec33b9245e1d1aa6e1f7e8132101#diff-ad02984d873efb089aa51551bc6b7d307a53e0ba1ac439e91d69c2e58a478864"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/ruby/webrick"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/rubysec/ruby-advisory-db/blob/master/gems/webrick/CVE-2025-6442.yml"
  }, {
    "type" : "WEB",
    "url" : "https://www.zerodayinitiative.com/advisories/ZDI-25-414"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-444" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-06-27T21:58:15Z",
    "nvd_published_at" : "2025-06-25T17:15:40Z"
  }
}