---
id: CVE-2026-93955
title: A vulnerability was detected in grimmory-tools grimmory up to 3.3.3/3.4.1
summary: >-
  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…
severity: medium
cvss: 4.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N'
cwe:
  - CWE-285
  - CWE-639
vendor: grimmory-tools
product: grimmory
affected:
  - grimmory 3.3.0
  - grimmory 3.3.1
  - grimmory 3.3.2
  - grimmory 3.3.3
  - grimmory 3.4.0
  - grimmory 3.4.1
published: '2026-09-19'
updated: '2026-09-21'
sourceUpdated: '2026-09-21T21:17:20.133'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-93955'
references:
  - url: 'https://github.com/grimmory-tools/grimmory/'
    label: cna@vuldb.com
  - url: 'https://github.com/grimmory-tools/grimmory/issues/2431'
    label: cna@vuldb.com
  - url: >-
      https://github.com/grimmory-tools/grimmory/issues/2431#issuecomment-5384402858
    label: cna@vuldb.com
  - url: 'https://vuldb.com/cve/CVE-2026-93955'
    label: cna@vuldb.com
  - url: 'https://vuldb.com/submit/943921'
    label: cna@vuldb.com
  - url: 'https://vuldb.com/vuln/407914'
    label: cna@vuldb.com
  - url: 'https://vuldb.com/vuln/407914/cti'
    label: cna@vuldb.com
  - url: >-
      https://github.com/grimmory-tools/grimmory/issues/2431#issuecomment-5384402858
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - cve.org
  - exploit-available
epss: 0.00414
epssPercentile: 0.3299
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-21T20:12:51.031460Z'
ingestedAt: '2026-09-19T23:10:34.249Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.