CVE-2026-14933

Unblu Spark Cross-Site Scripting in Embedded Co-Browsing

Published Oct 20, 2026 CVSS 4.0 · 8.6 High EPSS < 1% KEV · Not listed
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.

Remediation

Vendor 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.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Unblu
Unblu spark
Vendors & Products Unblu
Unblu spark
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
NCSC.ch
Published
Updated
Oct 20, 2026, 3:28 PM
Reserved
Jul 7, 2026, 10:56 AM
Status
Deferred
Published
Oct 20, 2026, 12:17 PM
Modified
Oct 20, 2026, 7:28 PM