Log in Start free

Vulnerability · Published Sep 19, 2026 · Assigned by VulDB

CVE-2026-93955grimmory-tools grimmory Download Endpoint KoboController.java streamFileToResponse authorization

Medium 4.3

In plain English

A medium-severity authorization bypass via user-controlled key in grimmory from grimmory-tools. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 36% of all known vulnerabilities).

Severity (CVSS 3.1)4.3Medium
Exploit odds (30 days)0.4%top 64.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official description

A vulnerability was detected in grimmory-tools grimmory up to 3.3.3/3.4.1. Affected by this vulnerability is the function streamFileToResponse of the file backend/src/main/java/org/booklore/controller/KoboController.java of the component Download Endpoint. Performing a manipulation of the argument bookId results in authorization bypass. The attack may be initiated remotely. The exploit is now public and may be used. Issue #2431 is closed as completed, but its only comment states that the issue “has already been reported elsewhere.” No fixing commit or pull request is identified there.

Affected products (as reported)

VendorProductVersions
grimmory-tools grimmory 3.3.03.3.13.3.23.3.33.4.03.4.1

Weakness: CWE-639, CWE-285 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N/E:P/RL:X/RC:R

References