CVE-2026-123535— Tornado before 6.6 Cookie Attribute Injection via set_cookie max_age

Quick assessment

Affected

tornadoweb tornado

Exploitation

No confirmed in-the-wild exploitation; assess based on exposure

Recommended action

Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Tornado 6.6 之前的版本未对方法中的参数进行验证（该方法也被、和调用），导致攻击者可以注入额外的属性。当应用程序将受攻击者控制的输入作为参数传递时，攻击者能够嵌入、或等属性，从而将 Cookie 的作用范围扩大至父路径或其他子域名。

CVSS 4.2 · Medium EPSS 0.17% · P7 Updated Nov 08, 2026

Possible ATT&CK Techniques 2 AI

T1055 · Process Injection T1190 · Exploit Public-Facing Application

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Vulnerability Information

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Vulnerability Title

Tornado before 6.6 Cookie Attribute Injection via set_cookie max_age

Source: CVE Program / CVE List V5

Vulnerability Description

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.

Source: CVE Program / CVE List V5

CVSS Information

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

Source: CVE Program / CVE List V5

Vulnerability Type

输出中的特殊元素转义处理不恰当(注入)

Source: CVE Program / CVE List V5

Affected Products

Vendor	Product	Affected Versions	CPE	Subscribe
tornadoweb	tornado	0 ~ 6.6	-

II. Public POCs for CVE-2026-123535

#	POC Description	Source Link	Shenlong Link

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III. Intelligence Information for CVE-2026-123535

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Other References for CVE-2026-123535 (2)

https://github.com/tornadoweb/tornado/security/advisories/GHSA-c6v4-qj2h-f748 vendor-advisory
https://www.vulncheck.com/advisories/tornado-before-6.6-cookie-attribute-injection-via-set-cookie-max-age third-party-advisory

https://www.cve.org/CVERecord?id=CVE-2026-123535

IV. Related Vulnerabilities

Same product: tornado

Same vendor: tornadoweb

Same weakness: CWE-74