UBUNTU-CVE-2026-34831

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Source
https://ubuntu.com/security/CVE-2026-34831
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34831.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-34831
Upstream
  • CVE-2026-34831
Downstream
Published
2026-04-02T17:16:00Z
Modified
2026-04-17T10:35:37.109904Z
Severity
  • 4.8 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Files#fail sets the Content-Length response header using String#size instead of String#bytesize. When the response body contains multibyte UTF-8 characters, the declared Content-Length is smaller than the number of bytes actually sent on the wire. Because Rack::Files reflects the requested path in 404 responses, an attacker can trigger this mismatch by requesting a non-existent path containing percent-encoded UTF-8 characters. This results in incorrect HTTP response framing and may cause response desynchronization in deployments that rely on the incorrect Content-Length value. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.

References

Affected packages

Ubuntu:Pro:22.04:LTS / ruby-rack

Package

Name
ruby-rack
Purl
pkg:deb/ubuntu/ruby-rack@2.1.4-5ubuntu1.2+esm3?arch=source&distro=esm-apps/jammy

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

2.*
2.1.4-3
2.1.4-4
2.1.4-5
2.1.4-5ubuntu1
2.1.4-5ubuntu1+esm2
2.1.4-5ubuntu1+esm3
2.1.4-5ubuntu1+esm4
2.1.4-5ubuntu1+esm5
2.1.4-5ubuntu1.1
2.1.4-5ubuntu1.1+esm1
2.1.4-5ubuntu1.1+esm2
2.1.4-5ubuntu1.2
2.1.4-5ubuntu1.2+esm1
2.1.4-5ubuntu1.2+esm2
2.1.4-5ubuntu1.2+esm3

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "2.1.4-5ubuntu1.2+esm3",
            "binary_name": "ruby-rack"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34831.json"

Ubuntu:24.04:LTS / ruby-rack

Package

Name
ruby-rack
Purl
pkg:deb/ubuntu/ruby-rack@2.2.7-1ubuntu0.7?arch=source&distro=noble

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

2.*
2.2.4-3
2.2.7-1
2.2.7-1ubuntu0.1
2.2.7-1ubuntu0.2
2.2.7-1ubuntu0.3
2.2.7-1ubuntu0.4
2.2.7-1ubuntu0.5
2.2.7-1ubuntu0.6
2.2.7-1ubuntu0.7

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "2.2.7-1ubuntu0.7",
            "binary_name": "ruby-rack"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34831.json"

Ubuntu:25.10 / ruby-rack

Package

Name
ruby-rack
Purl
pkg:deb/ubuntu/ruby-rack@3.1.16-0.1ubuntu0.3?arch=source&distro=questing

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

2.*
2.2.7-1.1
3.*
3.1.16-0.1
3.1.16-0.1ubuntu0.1
3.1.16-0.1ubuntu0.2
3.1.16-0.1ubuntu0.3

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "3.1.16-0.1ubuntu0.3",
            "binary_name": "ruby-rack"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34831.json"