CVE-2025-20247 Overview
CVE-2025-20247 is a reflected cross-site scripting (XSS) vulnerability in Cisco Webex Meetings. The flaw stems from improper filtering of user-supplied input within the web interface [CWE-79]. An unauthenticated, remote attacker can exploit the issue by convincing a target user to click a crafted link.
Successful exploitation executes arbitrary script code in the context of the victim's browser session. The attacker can then access sensitive browser-based information or perform actions on behalf of the user against the Webex interface.
Critical Impact
Attackers can execute arbitrary script in a victim's browser session by luring the user to follow a malicious Webex link, enabling session data theft and interface manipulation.
Affected Products
- Cisco Webex Meetings
- CPE: cpe:2.3:a:cisco:webex_meetings:-:*:*:*:*:*:*:*
- Vendor: Cisco Systems
Discovery Timeline
- 2025-05-21 - CVE-2025-20247 published to the National Vulnerability Database
- 2026-06-17 - Last updated in the NVD database
Technical Details for CVE-2025-20247
Vulnerability Analysis
The vulnerability resides in the Cisco Webex Meetings web interface. Cisco Webex fails to properly sanitize or encode user-supplied input before reflecting it in an HTTP response. This behavior maps to [CWE-79], Improper Neutralization of Input During Web Page Generation.
Exploitation requires user interaction. The attacker must persuade an authenticated or unauthenticated user to follow a URL that carries the malicious payload as a request parameter. Once loaded, the payload executes within the trust boundary of the Webex origin.
Because the scope changes at exploitation time, injected script can affect resources beyond the immediate vulnerable component. The confidentiality and integrity impact are limited but meaningful: an attacker can read accessible page content, extract tokens exposed to JavaScript, or trigger authenticated requests on behalf of the victim.
Root Cause
The root cause is insufficient output encoding of request-supplied values rendered back into HTML or JavaScript contexts. The web application trusts input parameters that should be treated as untrusted user data. Cisco addressed the flaw in the fixed builds referenced in the Cisco Security Advisory.
Attack Vector
The attack vector is network-based and requires user interaction. A typical exploitation flow involves the attacker crafting a Webex URL that embeds an XSS payload in a vulnerable parameter. The attacker then distributes the link through phishing email, chat, or a controlled web page.
When the victim opens the link, the Webex server reflects the payload into the rendered page, and the browser executes the injected script under the Webex origin. See the vendor advisory for technical details and fixed release information.
Detection Methods for CVE-2025-20247
Indicators of Compromise
- Inbound Webex Meetings URLs containing HTML control characters such as <, >, ", or encoded equivalents (%3C, %3E) inside request parameters.
- Web proxy or browser telemetry showing Webex pages executing script that references external attacker-controlled domains.
- Unexpected outbound connections from user browsers to unfamiliar hosts immediately after visiting a Webex link.
Detection Strategies
- Inspect HTTP request logs for Webex query strings containing JavaScript keywords such as onerror=, onload=, <script, or javascript:.
- Deploy web application firewall (WAF) signatures that flag reflected XSS patterns targeting Webex hostnames.
- Correlate email gateway telemetry with endpoint browsing history to identify users who received and clicked suspicious Webex URLs.
Monitoring Recommendations
- Enable Content Security Policy (CSP) violation reporting on managed browsers to surface script execution from unexpected sources.
- Forward browser, proxy, and email telemetry to a centralized analytics platform for cross-source correlation of phishing-to-click sequences.
- Track user reports of unexpected Webex behavior, prompts, or redirects as low-noise leading indicators.
How to Mitigate CVE-2025-20247
Immediate Actions Required
- Apply the fixed Cisco Webex Meetings releases identified in the Cisco Security Advisory cisco-sa-webex-xss-7teQtFn8.
- Notify users that Webex links from untrusted senders should not be opened until patches are confirmed deployed.
- Review email and messaging gateway rules to quarantine URLs with encoded script payloads targeting Webex domains.
Patch Information
Cisco has published fixed software for Cisco Webex Meetings. Administrators should consult the Cisco Security Advisory for the specific fixed builds applicable to their deployment and confirm cloud-hosted tenants are running the patched release.
Workarounds
- No vendor workaround is listed; user awareness training reduces the likelihood of link-based exploitation.
- Enforce browser policies that block execution of inline scripts from reflected parameters where feasible.
- Restrict access to Webex Meetings interfaces from unmanaged devices until patching is complete.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
