CVE-2026-116020: BookStackApp BookStack

BookStack before 26.09.2 Incorrect Authorization via AttachmentController on Draft Pages

CVSS 5.3 MediumEPSS 0.0018 · 7th percentile

Published by the CVE Program (CNA: VulnCheck) at 24 Oct 2026, 11:40 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it.

Affected products, as the CNA wrote them
Vendor	Product	Versions
BookStackApp	BookStack	affected before 26.09.2 custom Other versions: unaffected

Identifiers

CVE-2026-116020

CNA

VulnCheck

Weakness (CWE)

CWE-863

Not analysed yet

We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
5.3	Medium	4.0	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N	CNA (VulnCheck)Used for this record
5.4	Medium	3.1	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N	CNA (VulnCheck)

CISA KEV Not listed.
EPSS 0.0018, the 7th percentile, on 8 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

24 Oct 2026, 11:40 UTC Confirmed by the CVE List
24 Oct 2026, 12:16 UTC Confirmed by NVD

Sources

References from the CNA

codeberg.org/bookstack/bookstack/commit/fcadecccda706b4ecaf9ac3f8e27defe0ebe78ae patch
www.bookstackapp.com/blog/bookstack-release-v26-09-2/ vendor-advisoryrelease-notes
codeberg.org/bookstack/bookstack/releases/tag/v26.09.2 release-notes
codeberg.org/bookstack/bookstack/src/tag/v26.09.1/app/Uploads/Controllers/AttachmentController.php technical-description
www.vulncheck.com/advisories/bookstack-before-26.09.2-incorrect-authorization-via-attachmentcontroller-on-draft-pages third-party-advisory

Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description.