DEBIAN-CVE-2026-26961

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Source
https://security-tracker.debian.org/tracker/CVE-2026-26961
Import Source
https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-26961.json
JSON Data
https://api.osv.dev/v1/vulns/DEBIAN-CVE-2026-26961
Upstream
Published
2026-04-02T17:16:21Z
Modified
2026-09-14T17:02:53Z
Severity
  • 5.3 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N CVSS Calculator
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::Multipart::Parser extracts the boundary parameter from multipart/form-data using a greedy regular expression. When a Content-Type header contains multiple boundary parameters, Rack selects the last one rather than the first. In deployments where an upstream proxy, WAF, or intermediary interprets the first boundary parameter, this mismatch can allow an attacker to smuggle multipart content past upstream inspection and have Rack parse a different body structure than the intermediary validated. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.

References

Affected packages

Debian:12 / ruby-rack

Package

Name
ruby-rack
Purl
pkg:deb/debian/ruby-rack?arch=source&distro=bookworm

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
2.2.22-0+deb12u2

Affected versions

2.*
2.2.6.4-1
2.2.6.4-1+deb12u1
2.2.7-1
2.2.7-1.1
2.2.13-1~deb12u1
2.2.20-0+deb12u1
2.2.22-0+deb12u1

Ecosystem specific 

{
    "urgency":  "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-26961.json"

Debian:13 / ruby-rack

Package

Name
ruby-rack
Purl
pkg:deb/debian/ruby-rack?arch=source&distro=trixie

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
3.1.20-0+deb13u2

Affected versions

3.*
3.1.16-0.1
3.1.18-1~deb13u1
3.1.18-1
3.1.20-0+deb13u1

Ecosystem specific 

{
    "urgency":  "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-26961.json"

Debian:14 / ruby-rack

Package

Name
ruby-rack
Purl
pkg:deb/debian/ruby-rack?arch=source&distro=forky

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
3.2.6-2

Affected versions

3.*
3.1.16-0.1
3.1.18-1~deb13u1
3.1.18-1
3.2.4-1
3.2.5-1
3.2.5-2
3.2.6-1

Ecosystem specific 

{
    "urgency":  "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-26961.json"