CVE-2026-91991

Summary

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.

Affected Software

VendorProductVersion RangeStatus
tornadowebtornado6.5.5 < 6.5.8affected
tornadowebtornado6.5.8unaffected

Weaknesses

  • CWE-113: Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')

References