Skip to main content
CVE-2026-123535VulnerabilityPublished Updated

Python tornado: Tornado before 6.6 does not validate the max_age argument of RequestHandler.set_cookie (also called by

Affects python-tornadoSource GCVE Database

0
Compare
Authoritative record:CVE-2026-123535· Low 2.3

Not known to be exploited · CVSS 2.3 Low.

Data as of 12 Nov 2026, 22:18 UTC

CVSS 4.0 base score
2.3Low
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (VulnCheck)CVSS 4.02.3
CNA (VulnCheck)CVSS 3.14.2
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 8 Nov 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 12 Nov 2026.

What to do

Affected software

ProductAffectedFixed in
Ubuntu 26.10python-tornadopkg:deb/ubuntu/python-tornado?arch=source&distro=stonkingOther threatsAffected
  • 6.5.4-0.1 – 6.5.5-5ubuntu1.3
7 affected builds
Fixed in–
Ubuntu 26.04 LTSpython-tornadopkg:deb/ubuntu/python-tornado?arch=source&distro=resoluteOther threatsAffected
  • 6.4.2-3 – 6.5.4-0.1ubuntu0.4
7 affected builds
Fixed in–
Ubuntu 24.04 LTSpython-tornadopkg:deb/ubuntu/python-tornado?arch=source&distro=nobleOther threatsAffected
  • 6.3.2-1 – 6.4.0-1ubuntu0.8
11 affected builds
Fixed in–
Ubuntu Pro 22.04 LTSpython-tornadopkg:deb/ubuntu/python-tornado?arch=source&distro=esm-apps/jammyOther threatsAffected
  • 6.1.0-1build1 – 6.1.0-3ubuntu0.1~esm8
11 affected builds
Fixed in–
Ubuntu Pro 20.04 LTSpython-tornadopkg:deb/ubuntu/python-tornado?arch=source&distro=esm-apps/focalOther threatsAffected
  • 5.1.1-4ubuntu1 – 6.0.3+really5.1.1-3ubuntu0.1~esm9
12 affected builds
Fixed in–
Ubuntu Pro 18.04 LTSpython-tornadopkg:deb/ubuntu/python-tornado?arch=source&distro=esm-apps/bionicOther threatsAffected
  • 4.5.1-2.1~build2 – 4.5.3-1ubuntu0.2+esm6
11 affected builds
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Until a fix is available, avoid passing untrusted input to the max_age argument in cookie-setting methods to prevent injection of additional Set-Cookie attributes.

Description

Tornado versions before 6.6 do not validate the max_age argument in the RequestHandler.set_cookie method and related cookie-setting methods. This flaw allows an attacker to inject additional Set-Cookie attributes by supplying malicious input as max_age, potentially expanding the cookie's scope to parent paths or other subdomains. The vulnerability has a medium severity rating with a CVSS score of 4.2.

References

Community reviews

Loading reviews…