CVE-2025-3519: high-severity vulnerability in Unblu Spark
Replace uploaded files knowing the file upload ID
Published
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7epss 0.3%
An authorization bypass in Unblu Spark allows a participant of a conversation to replace an existing, uploaded file.
Every uploaded file in Unblu gets assigned with a randomly generated Universally Unique ID (UUID). In case a participant of this or another conversation gets access to such a file ID, it can be used to replace the file without changing the file name and details or the name of the user who uploaded the file. During the upload, file interception and allowed file type rules are still applied correctly.
CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N
Affected products
Unblu inc. · Unblu SparkRelated CVEs — Unblu Spark
In the same product, most dangerous first.
CVE-2026-14933HIGHUnblu Spark Cross-Site Scripting in Embedded Co-BrowsingEPSS 0.6%CVE-2026-8152CRITICALUnblu Spark Open Redirect leading to DOM-Based XSSEPSS 0.4%CVE-2026-9589CRITICALUnblu Spark Authorization Bypass in Configuration Cascade OperationsEPSS 0.4%CVE-2025-3518MEDIUMFile upload functionality possible even when disabledEPSS 0.2%