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Meeting ServerApplication · Cisco

CVE-2017-12311

MEDIUM · 5.8 CVSS v3.0 Published 2017-11-16
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
67/100
Remediation priority · Elevated
Remotely reachable No privileges 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 the H.264 decoder function of Cisco Meeting Server could allow an unauthenticated, remote attacker to cause a Cisco Meeting Server media process to restart unexpectedly when it receives an illegal H.264 frame. The vulnerability is triggered by an H.264 frame that has an invalid picture parameter set (PPS) value. An attacker could exploit this vulnerability by sending a malformed H.264 frame to the targeted device. An exploit could allow the attacker to cause a denial of service (DoS) condition because the media process could restart. The media session should be re-established within a few seconds, during which there could be a brief interruption in service. Cisco Bug IDs: CSCvg12559.

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

The Cisco Meeting Server H.264 decoder does not properly validate picture parameter set (PPS) values in incoming H.264 video frames. An unauthenticated remote attacker can send a malformed H.264 frame containing an invalid PPS value, causing the media process to crash and restart unexpectedly, resulting in a denial of service condition with brief service interruption.

MitigationApply the Cisco patch for CSCvg12559 when available. If no patch exists, consider network-level filtering to limit exposure of the Cisco Meeting Server to untrusted networks, and monitor for repeated service disruptions indicating active exploitation.

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
Meeting ServerApplication
Affected:= 2.0= 2.1.0= 2.2.0= 2.3.0

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
None
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
Low

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L

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. Confirm Cisco Meeting Server is installed
    Identify if the Cisco Meeting Server application is present in your environment. This may be evident from software inventory, running processes, or system documentation.
    Affected if The product is not Cisco Meeting Server, this CVE does not apply.
  2. Check installed version
    Determine the exact version number of the Cisco Meeting Server installation. Compare it against the affected versions: 2.0, 2.1.0, 2.2.0, or 2.3.0.
    Affected if The version matches exactly 2.0, 2.1.0, 2.2.0, or 2.3.0, the environment is potentially affected.
  3. Verify H.264 media processing is in use
    Determine if H.264 video decoding is enabled or actively used. This may involve checking media server configuration, active call recordings, or codec settings.
    Affected if H.264 decoding is not configured or in use, the specific attack vector may not be reachable.
  4. Assess network exposure
    Evaluate whether the Cisco Meeting Server is directly accessible from untrusted networks. Check firewall rules, VPN policies, and public-facing service configurations.
    Affected if The server is exposed to untrusted network segments, an unauthenticated attacker could reach the vulnerable component.

You are affected if Cisco Meeting Server version 2.0, 2.1.0, 2.2.0, or 2.3.0 is installed and H.264 video processing is enabled while the service is network-accessible to untrusted users.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the Cisco patch for CSCvg12559 when available. If no patch exists, consider network-level filtering to limit exposure of the Cisco Meeting Server to untrusted networks, and monitor for repeated service disruptions indicating active exploitation.

Fix this in Meeting Server Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA3.0 h
16.0 hours of engineering $2,760
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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-2017-12311 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