Authorization Bypass in grimmory-tools Download Endpoint
CVE-2026-93955

5.3MEDIUM

Key Information:

Vendor

Grimmory-tools

Status
Grimmory
Vendor
CVE Published:
19 September 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-93955?

A vulnerability in grimmory-tools' Download Endpoint allows an attacker to bypass authorization controls via manipulation of the bookId argument in the streamFileToResponse function of KoboController.java. This exploit can be initiated remotely, potentially exposing sensitive data or services to unauthorized access. Despite being reported, no fixes have been committed or merged, leaving affected versions vulnerable to exploitation.

Affected Version(s)

grimmory 3.3.0

grimmory 3.3.1

grimmory 3.3.2

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-2026-93955 - Proof of Concept

References

https://vuldb.com/vuln/407914
vdb-entrytechnical-description
https://vuldb.com/vuln/407914/cti
signaturepermissions-required
https://vuldb.com/cve/CVE-2026-93955
third-party-advisory

CVSS V4

Score:
5.3
Severity:
MEDIUM
Confidentiality:
Low
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

summmm (VulDB User)
VulDB CNA Team
.