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JabberApplication · Cisco

CVE-2020-3495

HIGH · 8.8 CVSS v3.1 Published 2020-09-04
Fix available
A fix is available. Upgrade to 12.1.3 / 12.5.2 or later.
See remediation →
94/100
Remediation priority · Urgent
High EPSS Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A vulnerability in Cisco Jabber for Windows could allow an authenticated, remote attacker to execute arbitrary code. The vulnerability is due to improper validation of message contents. An attacker could exploit this vulnerability by sending specially crafted Extensible Messaging and Presence Protocol (XMPP) messages to the affected software. A successful exploit could allow the attacker to cause the application to execute arbitrary programs on the targeted system with the privileges of the user account that is running the Cisco Jabber client software, possibly resulting in arbitrary code execution.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

A vulnerability in Cisco Jabber for Windows allows remote authenticated attackers to execute arbitrary code via specially crafted XMPP messages. The flaw stems from improper validation of message contents, enabling the attacker to cause the application to execute arbitrary programs with the privileges of the current user.

MitigationApply the relevant Cisco security update for Cisco Jabber for Windows when available; until then, restrict XMPP communications to trusted sources and monitor for suspicious XMPP traffic.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
JabberApplication
Affected:>= 12.1, < 12.1.3>= 12.5, < 12.5.2>= 12.6, < 12.6.3>= 12.7, < 12.7.2>= 12.8, < 12.8.3>= 12.9, < 12.9.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify Cisco Jabber for Windows is installed
    Check the Windows registry under HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\ for an entry named 'Cisco Jabber' or look for the executable at typical installation paths such as C:\Program Files\Cisco Systems\Cisco Jabber\Jabber.exe
    Affected if The software is present on the system
  2. Find the installed version of Cisco Jabber
    Right-click on Jabber.exe, select Properties, then view the Details tab for the Product Version, or run 'Get-ItemProperty' in PowerShell on the Jabber.exe file to retrieve the version
    Affected if The version falls within any of these ranges: 12.1.x before 12.1.3; 12.5.x before 12.5.2; 12.6.x before 12.6.3; 12.7.x before 12.7.2; 12.8.x before 12.8.3; 12.9.x before 12.9.1
  3. Confirm XMPP is the active protocol
    Open Cisco Jabber, go to Settings or Options, and check the account configuration to see which protocol (XMPP, SIP, or UCM) is enabled. Alternatively, check for XMPP-related configuration files in the application data folder (%APPDATA%\Cisco\Unified Communications\Jabber\CSF\Config)
    Affected if XMPP is enabled as the communication protocol; the vulnerability is exploitable specifically through XMPP message handling
  4. Check for suspicious XMPP traffic
    Use network monitoring tools or Windows Event Viewer to examine XMPP communications logs for unexpected messages, particularly from external or untrusted Jabber servers
    Affected if Unusual or unrecognized XMPP messages are observed originating from external sources

The system is affected if Cisco Jabber for Windows is installed with an affected version number AND XMPP protocol is enabled, allowing unauthenticated or authenticated attackers to send specially crafted XMPP messages to trigger arbitrary code execution.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to 12.1.3 / 12.5.2 / 12.6.3 or later
Fixed in 12.1.312.5.212.6.3
Interim mitigation

Apply the relevant Cisco security update for Cisco Jabber for Windows when available; until then, restrict XMPP communications to trusted sources and monitor for suspicious XMPP traffic.

Fix this in Jabber Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2020-3495 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data