Authorization Bypass Vulnerability in Semaphore UI by Semaphore
CVE-2026-91994

7.1HIGH

Key Information:

Vendor

Semaphoreui

Status
Semaphore
Vendor
CVE Published:
15 September 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-91994?

Semaphore UI versions up to and including 2.19.12 possess a significant authorization bypass issue within the GetMustCanMiddleware. This vulnerability allows attackers with guest or task_runner roles to bypass necessary permission checks for GET and HEAD requests. As a result, these unauthorized users can access all project environments and potentially extract sensitive information such as plaintext secrets, credentials, and passwords via GET requests to the environment endpoint.

Affected Version(s)

semaphore 0 <= 2.19.12

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-91994 - Proof of Concept

References

https://github.com/semaphoreui/semaphore/issues/4150
issue-trackingexploit
https://github.com/semaphoreui/semaphore/blob/v2.19.12/ap...
technical-description
https://github.com/semaphoreui/semaphore/blob/v2.19.12/ap...
technical-description

CVSS V4

Score:
7.1
Severity:
HIGH
Confidentiality:
High
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

George Chen
.