Cross-site scripting in the embedded co-browsing feature in Unblu inc. Unblu Spark 7.0 through 7.57.7 and 8.0 through 8.39.2, on on-premises and cloud deployments, allows an unauthenticated remote attacker in the visitor role to execute arbitrary JavaScript in the browser of an agent taking part in the attacker's co-browsing session, via content of the co-browsed page that the agent's browser renders as HTML.



The JavaScript runs in the context and under the identity of the agent's session in the Agent Desk or the Single Conversation Desk.



Exploitation requires an agent to join an embedded co-browsing session with the attacker. Mobile co-apping isn't affected.
Advisories

No advisories yet.

Fixes

Solution

Upgrade to Unblu Spark 8.39.3 or later, or 7.57.9 or later. The fix is also available in 8.35.2-hotfix.0, 8.37.2-hotfix.2, 8.38.2-hotfix.0 and later hotfixes of these release lines. Unblu Cloud customers needn't take any action. The fix is already deployed in Unblu Cloud. For a workaround for on-premises deployments that can't be upgraded immediately, see the security bulletin.


Workaround

No workaround given by the vendor.

History

Tue, 20 Oct 2026 12:45:00 +0000

Type Values Removed Values Added
Description Cross-site scripting in the embedded co-browsing feature in Unblu inc. Unblu Spark 7.0 through 7.57.7 and 8.0 through 8.39.2, on on-premises and cloud deployments, allows an unauthenticated remote attacker in the visitor role to execute arbitrary JavaScript in the browser of an agent taking part in the attacker's co-browsing session, via content of the co-browsed page that the agent's browser renders as HTML. The JavaScript runs in the context and under the identity of the agent's session in the Agent Desk or the Single Conversation Desk. Exploitation requires an agent to join an embedded co-browsing session with the attacker. Mobile co-apping isn't affected.
Title Unblu Spark Cross-Site Scripting in Embedded Co-Browsing
Weaknesses CWE-79
References
Metrics cvssV4_0

{'score': 8.6, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: NCSC.ch

Published:

Updated: 2026-10-20T11:08:43.830Z

Reserved: 2026-07-07T10:56:24.163Z

Link: CVE-2026-14933

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-20T12:17:30.057

Modified: 2026-10-20T12:17:30.057

Link: CVE-2026-14933

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses