P4Verified

CVE-2026-91991: tornado 6.5.5 to before 6.5.8

CVE-2026-91991. CVSS 3.1 base score 5.4 (MEDIUM, Vendor/CNA). EPSS 0.00247 (percentile 0.14576), scored 2026-10-06.

Affected technology

tornado · 6.5.5 to before 6.5.8
tornadoweb

Description’s affected range: before 6.5.8

Component: Not specified by the source

Attack conditions (Vendor/CNA, CVSS 4.0): Network (remote) · No privileges required · No user interaction required

What an attacker can do

Attackers can embed semicolon-delimited data in capitalized parameters like Domain, Path, or SameSite to bypass validation and modify cookie security attributes. Vendor/CNA’s CVSS 4.0 assessment (base score 6.3/10) rates confidentiality and integrity impact as low; availability impact as none.

Published 2026-10-08 17:35:08.390244+00:00

CWE: CWE-113
CCR priority: 21.7 /100 (P4)
CVSS 3.1: 5.4 /10 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N · Vendor/CNA
EPSS: 0.00247 · percentile 0.14644 · 2026-10-08
KEV: no

Provenance

FIRST EPSS daily exploit-probability · Source record · observed 2026-10-08 17:36:22.845483+00:00 UTC
NVD CVE API 2.0 · Source record · observed 2026-10-08 17:32:11.049884+00:00 UTC

Stable permalink: https://cybercodered.org/item/cve-cve-2026-91991.html