---
id: "CVE-2026-14933"
kind: "vulnerability"
aliases: ["CVE-2026-14933"]
title: "Unblu Spark: co-browsing flaw lets visitors run scripts in agent browsers"
severity: "high"
cvss: 8.6
epss: null
exploited: false
status: "open"
category: "vendor"
products: [{"name": "Unblu Spark", "fixed": ["8.35.2-hotfix.0", "8.37.2-hotfix.2", "8.38.2-hotfix.0", "8.39.3"], "affected": ">= 8.0, <= 8.39.2 (except 8.35.2-hotfix.0, 8.37.2-hotfix.2, 8.38.2-hotfix.0 and later hotfixes)", "ecosystem": "vendor"}, {"name": "Unblu Spark v7", "fixed": ["7.57.9"], "affected": ">= 7.0, <= 7.57.7", "ecosystem": "vendor"}]
ecosystems: []
tags: ["cloud", "co-browsing", "customer-support", "self-hosted", "unblu", "unblu-spark", "vendor", "xss"]
not_affected_if: ["embedded-co-browsing-disabled", "mobile-co-apping", "mobile-co-apping-only", "no-embedded-co-browsing", "unblu-cloud"]
published_at: "2026-10-20T12:17:30+00:00"
first_seen_at: "2026-10-23T21:57:20+00:00"
updated_at: "2026-10-24T00:13:53+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-14933", "first_seen_at": "2026-10-23T21:57:20+00:00"}, {"source": "analyst", "url": null, "first_seen_at": "2026-10-24T00:13:53+00:00"}]
---

# Unblu Spark: co-browsing flaw lets visitors run scripts in agent browsers

Unblu Spark co-browsing: a visitor can alter the co-browsed page (the selected option of a dropdown is rendered as HTML in the agent's browser) and run JavaScript as the agent in Agent Desk or Single Conversation Desk. Needs an agent to join the visitor's embedded co-browsing session. Mobile co-apping not affected. Unblu Cloud already fixed.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Unblu Spark affected >= 8.0, <= 8.39.2 (except 8.35.2-hotfix.0, 8.37.2-hotfix.2, 8.38.2-hotfix.0 and later hotfixes) fixed 8.35.2-hotfix.0, 8.37.2-hotfix.2, 8.38.2-hotfix.0, 8.39.3
- vendor:Unblu Spark v7 affected >= 7.0, <= 7.57.7 fixed 7.57.9

## How to check

On-premises: check the Unblu Spark version. Affected: 7.x up to 7.57.7, 8.x up to 8.39.2 unless on a fixed hotfix (8.35.2-hotfix.0, 8.37.2-hotfix.2, 8.38.2-hotfix.0 or later). Also check whether embedded co-browsing is enabled: com.unblu.messenger.embeddedCoBrowsingEnabled.

## Fix

Upgrade to 8.39.3 or later, 7.57.9 or later, or the hotfix of your line (8.35.2-hotfix.0, 8.37.2-hotfix.2, 8.38.2-hotfix.0). If you cannot upgrade, set com.unblu.messenger.embeddedCoBrowsingEnabled to false. Unblu Cloud: no action.

## Timeline

- 2026-10-23T21:57:20+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-14933
- 2026-10-24T00:13:53+00:00 analyst — Vendor bulletin UBL-2026-004 (docs.unblu.com, 2026-10-15): fixes 8.35.2-hotfix.0, 8.37.2-hotfix.2, 8.38.2-hotfix.0, 8.39.3, 7.57.9; Cloud already patched; workaround for on-prem. No exploitation or PoC found; X count shows no conversation. Root cause: selected <option> text of dropdowns in co-browsed page rendered as HTML in agent browser.

## Documents

- [advisory] Unblu security bulletin UBL-2026-004 (CVE-2026-14933) https://docs.unblu.com/latest/security-bulletins/#UBL-2026-004
- [describes] CVE Record CVE-2026-14933 https://www.cve.org/CVERecord?id=CVE-2026-14933

## From the sources

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.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_