4.3
MEDIUM CVSS 3.1
CVE-2026-93955
grimmory-tools grimmory Download Endpoint KoboController.java streamFileToResponse authorization
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.

INFO

Published Date :

Sept. 19, 2026, 11:17 p.m.

Last Modified :

Sept. 21, 2026, 9:17 p.m.

Remotely Exploit :

Yes !
Affected Products

The following products are affected by CVE-2026-93955 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Grimmory-tools grimmory
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 134c704f-9b21-4f2e-91b3-4a467353bcc0
CVSS 2.0 MEDIUM [email protected]
CVSS 3.1 MEDIUM [email protected]
CVSS 4.0 LOW [email protected]
Solution
Address authorization bypass by updating grimmory-tools to a version that fixes the streamFileToResponse vulnerability.
  • Update grimmory-tools to a patched version.
  • Verify the patch addresses the streamFileToResponse flaw.
  • Review access controls for the Download Endpoint.
  • Monitor for further exploit attempts.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-93955 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-93955 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-93955 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-93955 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Sep. 21, 2026

    Action Type Old Value New Value
    Added Reference https://github.com/grimmory-tools/grimmory/issues/2431#issuecomment-5384402858
    Added SSVC {'id': 'CVE-2026-93955', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-09-21T20:12:51.031460Z'}
  • New CVE Received by [email protected]

    Sep. 19, 2026

    Action Type Old Value New Value
    Added 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.
    Added CVSS V4.0 AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
    Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
    Added CVSS V2 (AV:N/AC:L/Au:S/C:P/I:N/A:N)
    Added CWE CWE-285
    Added CWE CWE-639
    Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/93xxx/CVE-2026-93955.json">CVE-2026-93955</a>
    Added Reference https://github.com/grimmory-tools/grimmory/
    Added Reference https://github.com/grimmory-tools/grimmory/issues/2431
    Added Reference https://github.com/grimmory-tools/grimmory/issues/2431#issuecomment-5384402858
    Added Reference https://vuldb.com/cve/CVE-2026-93955
    Added Reference https://vuldb.com/submit/943921
    Added Reference https://vuldb.com/vuln/407914
    Added Reference https://vuldb.com/vuln/407914/cti
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.