IM
IronMonkey Threat Research

CVE-2026-84695 CRITICAL

Published: 2026-09-02 | Last Modified: 2026-09-02 | Status: Received

Description

BookStack before 26.05.4 contains a stored cross-site scripting vulnerability in the drawing upload endpoint that accepts unvalidated base64 content and stores it without content inspection. Attackers with editor permissions can upload SVG files containing scripts that execute in administrator browsers when accessed through the image gallery API without content-type validation or CSP headers.

CVSS Metrics

Base Score: 8.7 (HIGH)

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N

Attack VectorNETWORK
Attack ComplexityLOW
Privileges RequiredLOW
User InteractionREQUIRED
ScopeCHANGED
Confidentiality ImpactHIGH
Integrity ImpactHIGH
Availability ImpactNONE

Source: [email protected]

Type: Primary

Exploitability Score: 2.3

Impact Score: 5.8

Base Score: 9.3 (CRITICAL)

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N/E:X/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

Attack VectorNETWORK
Attack ComplexityLOW
Attack RequirementsNONE
Privileges RequiredLOW
User InteractionPASSIVE
Vulnerability ConfidentialityHIGH
Vulnerability IntegrityHIGH
Vulnerability AvailabilityNONE
Subsequent ConfidentialityHIGH
Subsequent IntegrityHIGH
Subsequent AvailabilityNONE

Source: [email protected]

Type: Secondary

Weaknesses

Source Type Description
[email protected] Primary
en CWE-79
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