CVSS 4.0
2.3 lowCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:NCVE-2026-123535
Tornado before 6.6 Cookie Attribute Injection via set_cookie max_age
Low (2.3) in tornadoweb tornado. EPSS 0.2% estimated probability of exploitation activity in the next 30 days.
On this page
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.
Severity
CVSS 3.1
4.2 mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N- EPSS
- 0.2% estimated probability of exploitation activity in the next 30 days; 7th percentile. Scored 2026-11-12. A forecast for this CVE across the internet, not for your own systems.
- CISA's assessment (SSVC)
- Exploitation: none · Automatable: no · Technical impact: partial, assessed 2026-11-12. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
- CWE
- CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection)
- OWASP Top 10
- A05:2025 Injection
- Published
- Modified
- Assigned by
- VulnCheck (CNA)
- NVD analysis
- Deferred: the NVD does not plan to analyze it
- Record from
- the NVD, synced
Ask an AI about this CVE
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Explain CVE-2026-123535 for an engineer deciding whether to act. Use https://cve.bz/api/public/cves/CVE-2026-123535?via=ask-ai-copy and https://cve.bz/cve/CVE-2026-123535?via=ask-ai-copy as the source of truth: what is affected and which versions fix it, whether it is in CISA KEV, public exploits, and its EPSS (an internet-wide 30-day estimate of exploitation activity, not a forecast for my systems). If they give no fixed versions, use the CVE record https://cveawg.mitre.org/api/cve/CVE-2026-123535 or the vendor advisory, not third-party mirrors. Tell me how to check whether I am affected and how to verify a fix. Cite the sources and say where they are uncertain.Opens a third-party assistant; its answer is its own, not cve.bz's. The prompt holds only this CVE's id and public links.
Badge for a README or a site
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Affected
Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| tornadoweb tornado | before 6.6 |
Linux distributions
| Distribution | Release | Package | Fixed in | Advisory |
|---|---|---|---|---|
| Debian | 12, 13, 14 | python-tornado | no fix listed | DEBIAN-CVE-2026-123535 |
| Ubuntu | 24.04:LTS, 26.04:LTS, 26.10 and 4 more | python-tornado | no fix listed | UBUNTU-CVE-2026-123535 |
| Azure Linux | 3 | python-tornado | no fix listed | AZL-113107 |
From the distributions' data via OSV.dev: the Debian Security Tracker; Ubuntu Security Notices © Canonical Ltd., CC BY-SA 4.0; Microsoft's Azure Linux vulnerability data, MIT. Modified: reformatted and linked to CVE records. Credits. On the distributions' own pages: Debian · Ubuntu.
Attack patterns (CAPEC)
The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits. More on the page of CWE-74 (37).