Tornado before 6.5.8 Cookie Attribute Injection via Capitalized kwargs
Tornado before 6.5.8 contains an incomplete fix for cookie attribute injection that allows attackers to inject arbitrary cookie attributes by passing capitalized or legacy keyword arguments to set_cookie. Attackers can embed semicolon-delimited data in capitalized parameters like Domain, Path, or SameSite to bypass validation and modify cookie security attributes.
CVE-2026-91991
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: cve:CVE-2026-91991
tornado
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"vendor": "tornadoweb",
"product": "tornado",
"versions": [
{
"status": "affected",
"version": "6.5.5",
"lessThan": "6.5.8",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.5.8",
"versionType": "semver"
}
],
"packageURL": "pkg:pypi/tornado",
"defaultStatus": "unaffected"
}
]- Related CVEs
- CVE-2026-91991
Source reference:
/cveMetadata/cveId
Publisher severity
medium
Source reference: /containers/cna/metrics
- Event
- #12959 · Revision 1
- Added to Heist Feed
- Publisher date