CVE-2026-91991

medium

Tornado before 6.5.8 contains an incomplete fix for cookie attribute injection that allows attackers to inject arbitrary cookie attributes by passing capitaliz…

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.

CVSS

5.4

5.4 (CVSS v3.1)

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N

Severity source: NVD CVSS v3.1 (disclosure@vulncheck.com)

Timeline (UTC)

Published: 2026-09-15 16:17

Modified: 2026-10-08 16:17

NVD status: Deferred

Last synced 2 days ago

Verified against the source API 2026-10-27 06:53 UTC

Exploitation

Not listed in CISA KEV (as of last catalog sync)

Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).

Affected products

Not reported by the source (unknown — not "none").

Weakness classification (CWE)

CWE-113

Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.

Mitigation & advisories

No vendor advisory or patch reference tagged by NVD. Check the references below.

References

https://github.com/tornadoweb/tornado/security/advisories/GHSA-wwv5-g3v4-889x disclosure@vulncheck.com
https://www.vulncheck.com/advisories/tornado-before-6.5.8-cookie-attribute-injection-via-c... disclosure@vulncheck.com
https://github.com/tornadoweb/tornado/security/advisories/GHSA-wwv5-g3v4-889x 134c704f-9b21-4f2e-91b3-4a467353bcc0

Data sources

NVD CVE API 2.0 — fetched 2026-10-27 06:53 UTC · record ↗

Learn the basics

Understanding CVEs and CVSS Scores