DEBIAN-CVE-2026-34827
Rack is a modular Ruby web server interface. From versions 3.0.0.beta1 to before 3.1.21, and 3.2.0 to before 3.2.6, Rack::Multipart::Parser#handle_mime_head parses quoted multipart parameters such as Content-Disposition: form-data; name="..." using repeated String#index searches combined with String#slice! prefix deletion. For escape-heavy quoted values, this causes super-linear processing. An unauthenticated attacker can send a crafted multipart/form-data request containing many parts with long backslash-escaped parameter values to trigger excessive CPU usage during multipart parsing. This results in a denial of service condition in Rack applications that accept multipart form data. This issue has been patched in versions 3.1.21 and 3.2.6.
DEBIAN-CVE-2026-34827
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: osv:DEBIAN-CVE-2026-34827
ruby-rack
Source reference: /affected/0/package/name
- Affected versions
- 3.1.16-0.1
Source reference:
/affected/0/versions3.1.18-1Source reference:
/affected/0/versions3.1.18-1~deb13u1Source reference:
/affected/0/versions3.1.20-0+deb13u1Source reference:
/affected/0/versions - Fixed versions
- 3.1.20-0+deb13u2
Source reference:
/affected/0/ranges - Prerequisites
- Not stated in this record
ruby-rack
Source reference: /affected/1/package/name
- Affected versions
- 3.1.16-0.1
Source reference:
/affected/1/versions3.1.18-1Source reference:
/affected/1/versions3.1.18-1~deb13u1Source reference:
/affected/1/versions3.2.4-1Source reference:
/affected/1/versions3.2.5-1Source reference:
/affected/1/versions3.2.5-2Source reference:
/affected/1/versions3.2.6-1Source reference:
/affected/1/versions - Fixed versions
- 3.2.6-2
Source reference:
/affected/1/ranges - Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "3.1.20-0+deb13u2"
}
]
}
],
"package": {
"name": "ruby-rack",
"purl": "pkg:deb/debian/ruby-rack?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"3.1.16-0.1",
"3.1.18-1",
"3.1.18-1~deb13u1",
"3.1.20-0+deb13u1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-34827.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "3.2.6-2"
}
]
}
],
"package": {
"name": "ruby-rack",
"purl": "pkg:deb/debian/ruby-rack?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"3.1.16-0.1",
"3.1.18-1",
"3.1.18-1~deb13u1",
"3.2.4-1",
"3.2.5-1",
"3.2.5-2",
"3.2.6-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-34827.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
]Publisher severity
No explicit severity was provided.
- Event
- #57539 · Revision 1
- Added to Heist Feed
- Publisher date