CVE-2026-39324— Rack::Session::Cookie secrets: decrypt failure fallback enables secretless session forgery and Marshal deserialization
Quick assessment
Affected
rack rack-session
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.
Rack::Session是Official Rack repositories开源的一个应用程序。 Rack::Session 2.1.2之前版本存在安全漏洞，该漏洞源于Cookie解密失败处理不当，可能导致会话操纵和未经授权的访问。
Possible ATT&CK Techniques 1 AI
T1190 · Exploit Public-Facing Application
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I. Basic Information for CVE-2026-39324
Vulnerability Information
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Vulnerability Title
Rack::Session::Cookie secrets: decrypt failure fallback enables secretless session forgery and Marshal deserialization
Source: CVE Program / CVE List V5
Vulnerability Description
Rack::Session is a session management implementation for Rack. From 2.0.0 to before 2.1.2, Rack::Session::Cookie incorrectly handles decryption failures when configured with secrets:. If cookie decryption fails, the implementation falls back to a default decoder instead of rejecting the cookie. This allows an unauthenticated attacker to supply a crafted session cookie that is accepted as valid session data without knowledge of any configured secret. Because this mechanism is used to load session state, an attacker can manipulate session contents and potentially gain unauthorized access. This vulnerability is fixed in 2.1.2.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Source: CVE Program / CVE List V5
Vulnerability Type
认证机制不恰当
Source: CVE Program / CVE List V5
Vulnerability Title
Rack::Session 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Rack::Session是Official Rack repositories开源的一个应用程序。 Rack::Session 2.1.2之前版本存在安全漏洞，该漏洞源于Cookie解密失败处理不当，可能导致会话操纵和未经授权的访问。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| rack | rack-session | >= 2.0.0, < 2.1.2 | - |
|
II. Public POCs for CVE-2026-39324
| # | POC Description | Source Link | Shenlong Link |
|---|
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V. Comments for CVE-2026-39324
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