CVE-2025-6442

Publication date 25 June 2025

Last updated 27 October 2025

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

6.5 · Medium

Score breakdown

Description

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.

Status

Package Ubuntu Release Status
ruby-webrick 25.10 questing
Fixed 1.9.1-1
25.04 plucky
Fixed 1.8.1-1ubuntu1.1
24.10 oracular Ignored end of life, was needs-triage
24.04 LTS noble
Fixed 1.8.1-1ubuntu0.2
22.04 LTS jammy
Fixed 1.7.0-3ubuntu0.2
jruby 25.10 questing
Not affected
25.04 plucky
Not affected
24.04 LTS noble
Not affected
22.04 LTS jammy Not in release
20.04 LTS focal
Vulnerable
18.04 LTS bionic
Vulnerable
16.04 LTS xenial
Vulnerable
14.04 LTS trusty
Vulnerable
ruby2.3 25.10 questing Not in release
25.04 plucky Not in release
24.04 LTS noble Not in release
22.04 LTS jammy Not in release
16.04 LTS xenial
Fixed 2.3.1-2~ubuntu16.04.16+esm11
ruby2.5 25.10 questing Not in release
25.04 plucky Not in release
24.04 LTS noble Not in release
22.04 LTS jammy Not in release
18.04 LTS bionic
Fixed 2.5.1-1ubuntu1.16+esm6
ruby2.7 25.10 questing Not in release
25.04 plucky Not in release
24.04 LTS noble Not in release
22.04 LTS jammy Not in release
20.04 LTS focal
Fixed 2.7.0-5ubuntu1.18+esm3

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Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
ruby-webrick

Severity score breakdown

Parameter Value
Base score 6.5 · Medium
Attack vector Network
Attack complexity High
Privileges required None
User interaction None
Scope Unchanged
Confidentiality Low
Integrity impact High
Availability impact None
Vector CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N

References

Related Ubuntu Security Notices (USN)

Other references