CVE-2026-8152
Unblu Spark Open Redirect leading to DOM-Based XSS
- Published
- Updated
- Reserved
- Assigned by
- NCSC.ch
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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NCSC.chCNA (assigner) | 4.0 | Critical9.3 | 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 |
| NCSC.chCNA (assigner) | 4.0 | High7.0 | 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 |
| NVDNVD · Deferred | 4.0 | Critical9.3 | 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 |
- EPSS (exploitation in 30 days)
- 0.41% · top 64% of all CVEs (6 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.3.
Weakness
Affected products
- affected ≤ 8.36.1
- unaffected 8.36.1-hotfix.0
- unaffected 8.37.0
What to do
Solution: 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).
Workaround: 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:).
References (1)
- Unblu Security Advisories (opens in a new tab)vendor-advisory
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-8152)Record last updated .