CVE-2025-20215VulnerabilityPublished 6 Aug 2025

CVE-2025-20215: Cisco Webex Meetings · Improper Certificate Validation

Affects Cisco Webex MeetingsSource CVE Database V5

Not known to be exploited · CVSS 5.4 Medium.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score

5.4Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.1% chance of exploitation in 30 days – higher than 1% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:H/I:L/A:N

Attack Vector: Adjacent
Attack Complexity: High
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: High
Integrity: Low
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Adjacent: The vulnerable component is bound to the network stack, but the attack is limited at the protocol level to a logically adjacent topology. This can mean an attack must be launched from the same shared physical (e.g., Bluetooth or IEEE 802.11) or logical (e.g., local IP subnet) network, or from within a secure or otherwise limited administrative domain (e.g., MPLS, secure VPN to an administrative network zone).
Attack Complexity: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 6 Aug 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

AI-suggested

Although Cisco states no customer action is needed due to the patch being applied on the service side, European organizations should: 1) Verify that their Cisco Webex Meetings clients and services are updated to the latest versions to ensure the fix is in place. 2) Enforce the use of secure, encrypted, and trusted networks for joining meetings, avoiding public or unsecured Wi-Fi where possible. 3) Implement network segmentation and monitoring to detect unusual ARP spoofing or man-in-the-middle activities that could facilitate such attacks. 4) Educate users on the risks of joining meetings over untrusted networks and encourage use of VPNs when remote. 5) Monitor Cisco security advisories for any updates or related vulnerabilities. 6) Consider additional multi-factor authentication or meeting access controls to limit unauthorized join attempts. These measures go beyond generic advice by focusing on network security hygiene and user awareness tailored to the attack vector.

Description

A vulnerability in the meeting-join functionality of Cisco Webex Meetings could have allowed an unauthenticated, network-proximate attacker to complete a meeting-join process in place of an intended targeted user, provided the requisite conditions were satisfied. Cisco has addressed this vulnerability in the Cisco Webex Meetings service, and no customer action is needed. This vulnerability existed due to client certificate validation issues. Prior to this vulnerability being addressed, an attacker could have exploited this vulnerability by monitoring local wireless or adjacent networks for client-join requests and attempting to interrupt and complete the meeting-join flow as another user who was currently joining a meeting. To successfully exploit the vulnerability, an attacker would need the capability to position themselves in a local wireless or adjacent network, to monitor and intercept the targeted network traffic flows, and to satisfy timing requirements in order to interrupt the meeting-join flow and exploit the vulnerability. A successful exploit could have allowed the attacker to join the meeting as another user. However, the Cisco Product Security Incident Response Team (PSIRT) is not aware of any malicious use of the vulnerability that is described in this advisory.

Impact

For European organizations, this vulnerability poses a risk to the confidentiality of sensitive communications conducted over Cisco Webex Meetings. Unauthorized access to meetings could lead to exposure of intellectual property, strategic discussions, or personal data, potentially violating GDPR and other data protection regulations. The requirement for network proximity limits the attack surface primarily to environments where attackers can access local wireless or adjacent networks, such as corporate offices, public Wi-Fi hotspots, or shared facilities. This risk is heightened in organizations with remote or hybrid work models using public or unsecured networks. The integrity and availability of meetings are less impacted, but the confidentiality breach alone can have serious reputational and compliance consequences. Given Cisco Webex's widespread adoption among European enterprises, government agencies, and educational institutions, the vulnerability could affect a broad range of sectors. However, the absence of known exploits and the patch already applied by Cisco reduce immediate risk.

Summary

CVE-2025-20215 is a medium-severity vulnerability affecting Cisco Webex Meetings, specifically in the meeting-join functionality. The root cause is improper client certificate validation during the meeting join process. This flaw could allow an unauthenticated attacker positioned on a local wireless or adjacent network to intercept and hijack the meeting join flow of a targeted user. By monitoring network traffic for client join requests and satisfying strict timing requirements, the attacker could interrupt the legitimate join process and complete it themselves, effectively joining the meeting as the targeted user. This attack requires network proximity, the ability to monitor and intercept traffic, and precise timing to exploit the vulnerability. The vulnerability impacts confidentiality by allowing unauthorized meeting access, potentially exposing sensitive meeting content. Integrity impact is low since the attacker cannot alter meeting data or disrupt availability. Cisco has addressed this vulnerability in their Webex Meetings service, and no customer action is currently required. There are no known exploits in the wild. The CVSS v3.1 base score is 5.4, reflecting the attack vector (adjacent network), high attack complexity, no privileges required, user interaction required, unchanged scope, high confidentiality impact, low integrity impact, and no availability impact.

References

sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-webex-join-yNXfqHk4 (opens in a new tab)

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 6 Aug 2025, 16:48 UTC

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References

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