What is CVE-2026-93955?
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.
The record classifies CVE-2026-93955 under weakness classes CWE-639, CWE-285. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs low-privilege credentials, needs no user interaction. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 16 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 4.3 — MEDIUM
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 - CVSS v4.0 base score
- 5.3
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P - EPSS (FIRST)
- 0.3% probability of exploitation in the next 30 days, higher than 33.6% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 3.5/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-09-19
Is CVE-2026-93955 being exploited?
It currently carries a trending score of 38 in the Threadlinqs vulnerability feed.
Affected products and versions
- grimmory-tools: grimmory
How to fix CVE-2026-93955
No vendor patch reference has been recorded for CVE-2026-93955 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.
Threat activity tracking CVE-2026-93955
No threat campaign in the Threadlinqs corpus currently references CVE-2026-93955, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.
Sources
Enriched from CVE.org, FIRST EPSS. Last verified by Threadlinqs on .