Meeting ServerApplication · Cisco
CVE-2023-20255
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 · uneditedA vulnerability in an API of the Web Bridge feature of Cisco Meeting Server could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. This vulnerability is due to insufficient validation of HTTP requests. An attacker could exploit this vulnerability by sending crafted HTTP packets to an affected device. A successful exploit could allow the attacker to cause a partial availability condition, which could cause ongoing video calls to be dropped due to the invalid packets reaching the Web Bridge.
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 confidenceThe Cisco Meeting Server Web Bridge API has insufficient validation of HTTP requests, allowing unauthenticated remote attackers to send crafted HTTP packets that cause a partial denial of service condition, dropping ongoing video calls.
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
< 3.6.1CVSS 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
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- Low
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/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 checksWork through these to decide whether this CVE applies to you.
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Identify if Cisco Meeting Server is installedCheck for Cisco Meeting Server by reviewing installed software packages or the application directory. On the server, look for the cms command or check /opt/cisco/ meeting-server/ path structure.Affected if The software is present on the system
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Determine the installed version of Cisco Meeting ServerRun 'cms -v' or 'cms --version' from the command line, or check the version through the web admin interface under Status > Version.Affected if The installed version is lower than 3.6.1 (any version < 3.6.1)
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Verify if Web Bridge is enabledAccess the Cisco Meeting Server web admin interface and navigate to Configuration > Web Bridges, or check the configuration file for web bridge settings.Affected if Web Bridge is enabled and accessible
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Check network exposure of the Web Bridge interfaceReview firewall rules or network ACLs to determine if the Web Bridge port (typically TCP 443 or 8443) is exposed to unauthenticated/public network access.Affected if The Web Bridge HTTP/HTTPS interface is accessible from untrusted networks without authentication restrictions
A system is affected if Cisco Meeting Server version is below 3.6.1 AND the Web Bridge API is enabled and exposed to unauthenticated network traffic.
Generated from the published advisory. Verify against your own configuration.
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 data3.6.1
Apply the vendor patch when available; prior to patching, consider restricting access to the Web Bridge interface via firewall rules or network segmentation to limit exposure to unauthenticated HTTP traffic.
Fix this in Meeting Server
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-20255 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2023-20255 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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
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