Cookie attribute injection in Tornado via set_cookie max_age
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Passive
- Attack complexity
- Low
- Attack requirements
- Present
- Impact type
- —
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA.
Summary
Tornado before 6.6, a Python web framework from tornadoweb, does not validate the max_age argument of RequestHandler.set_cookie. When an application passes attacker-influenced input as max_age, an unauthenticated remote attacker who can get a victim to interact with the page can inject extra Set-Cookie attributes such as Domain, Path, or Secure. This widens the cookie's scope to parent paths or other subdomains, and the flaw is classified as CWE-74.
Written with Claude Haiku 5.5 from the sources below · 2026-11-08
Description from the CNA
Tornado before 6.6 does not validate the max_age argument of RequestHandler.set_cookie (also called by set_signed_cookie, set_secure_cookie, and clear_cookie), allowing injection of additional Set-Cookie attributes. When an application passes attacker-influenced input as max_age, an attacker can embed attributes such as Domain, Path, or Secure to widen the cookie's scope to parent paths or other subdomains.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| tornadoweb | tornado | before 6.6 | 6.6 | Patch available | CNA |
- tornado Vendortornadoweb Affected before 6.6 Fixed in 6.6 Patch available CNA
CPE names Threatist (inferred) · 1
Inferred from how NVD named this product before; not given by a source.
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:tornadoweb:tornado:*:*:*:*:*:*:*:* | — | — | tornadoweb |
- cpe:2.3:a:tornadoweb:tornado:*:*:*:*:*:*:*:* Versions — — ·tornadoweb
Remediation
Upgrade tornado to version 6.6 or later, which fixes the flaw.
Written with Claude Haiku 5.5 from the sources below · 2026-11-08
- Fix · CNA tornado (tornadoweb) Fixed in 6.6
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Release ·
tornadoweb tornado 6.6
2 records Highest priority Priority MEDIUM 1 MEDIUM, 1 LOW
Other records, highest priority first
- TI-2026-86676 Path traversal in Tornado static_url() version hashingPriority MEDIUM 51
Timeline
- 2026-11-08 Threatist record created from CVE-2026-123535
- 2026-11-08 Alias added: GHSA-cfc4-jgx9-vvjh
References
More tornadoweb vulnerabilities
- TI-2026-65637 Tornado before 6.5.9 Denial of Service via CurlAsyncHTTPClient CVSS 4.0HIGH 8.7
- TI-2026-62120 Tornado before 6.5.8 Memory Amplification DoS via multipart CVSS 4.0HIGH 8.7
- TI-2024-13023 Tornado before 6.4.1 HTTP Request Smuggling via Transfer-Encoding CVSS 4.0CRITICAL 9.0
- TI-2026-65638 Tornado before 6.5.9 StaticFileHandler Path Traversal via Symlink CVSS 4.0HIGH 8.2
- TI-2026-62122 Tornado before 6.5.7 Credential Leak via Handle Reuse CVSS 4.0HIGH 8.2
- TI-2026-62121 Tornado before 6.5.8 Cookie Attribute Injection via Capitalized kwargs CVSS 4.0MEDIUM 6.3
Sources
- CVE-2026-123535 · CVE Program
- CVE-2026-123535 · NVD
- GHSA-cfc4-jgx9-vvjh · GitHub Advisory Database · CC BY 4.0
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