Unblu Spark Open Redirect leading to DOM-Based XSS
Summary
| CVE | CVE-2026-8152 |
|---|---|
| State | PUBLISHED |
| Assigner | NCSC.ch |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-07-22 13:16:38 UTC |
| Updated | 2026-07-22 19:17:14 UTC |
| Description | Unblu Spark contains an open redirect vulnerability that can be escalated to a DOM-based cross-site scripting (XSS) attack. When Unblu Spark is deployed with com.unblu.identifier.siteEmbeddedSetup=true, it runs in the same origin as the host application. Any JavaScript injected through this vulnerability therefore executes with full access to the host application's cookies, DOM, and same-origin APIs — an attacker can reach all resources of the host application, not just Unblu's. This expanded blast radius is the reason on-premises deployments using this configuration are rated CRITICAL. |
Risk And Classification
Primary CVSS: v4.0 9.3 CRITICAL from [email protected]
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/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
Problem Types: CWE-79 | CWE-601 | CWE-601 CWE-601 URL Redirection to Untrusted Site ('Open Redirect') | CWE-79 CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | [email protected] | Secondary | 9.3 | CRITICAL | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N/E:X/C... |
| 4.0 | CNA | CVSS | 9.3 | CRITICAL | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N |
| 4.0 | CNA | CVSS | 7 | HIGH | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N |
CVSS v4.0 Breakdown
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/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
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Unblu Inc. | Unblu Spark | affected 8.36.1 semver | On-premises, Cloud |
| CNA | Unblu Inc. | Unblu Spark | unaffected 8.36.1-hotfix.0 semver | On-premises, Cloud |
| CNA | Unblu Inc. | Unblu Spark | unaffected 8.37.0 semver | On-premises, Cloud |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| docs.unblu.com/latest/security-bulletins | [email protected] | docs.unblu.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Kenan Karalioglu (chef_shell) via YesWeHack (en)
Additional Advisory Data
Solutions
CNA: In the fix versions listed above, Unblu Spark validates all user-supplied redirects through the same redirect filter. After upgrading, please review your redirect filter configuration. The defaults restrict redirects to the current origin (document.location.origin).
Workarounds
CNA: If you cannot upgrade immediately, either of the following measures prevents exploitation: * Enable the built-in Content Security Policy by setting com.unblu.contentsecuritypolicy.mode=on. The CSP blocks the injected JavaScript from executing and prevents the exploit from succeeding. Note: this protection is only effective on Unblu Spark 7.56.2 or later in the 7.x series and 8.19.1 or later in the 8.x series, where unsafe-inline was removed from the script source policy. Earlier versions ship a CSP that still permits unsafe-inline and are not protected by this workaround. * Configure a WAF rule to block requests that carry a malicious payload in the redirectOnFailure parameter (in particular, values containing a javascript: scheme or obfuscated variants such as java%0ascript:).