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Median 500l Msbr FirmwareOperating system · Audiocodes

CVE-2019-9228

HIGH · 7.5 CVSS v3.0 Published 2019-07-19
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
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
An issue was discovered on AudioCodes Mediant 500L-MSBR, 500-MBSR, M800B-MSBR and 800C-MSBR devices with firmware versions F7.20A at least to 7.20A.252.062. The (1) management SSH and (2) management TELNET features allow remote attackers to cause a denial of service (connection slot exhaustion) via 5 unauthenticated connection attempts, because the maximum number of unauthenticated clients that can be configured is 5. NOTE: the vendor's position is that this is a "design choice.

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

On AudioCodes Mediant 500L-MSBR, 500-MBSR, M800B-MSBR and 800C-MSBR devices with firmware F7.20A through 7.20A.252.062, the management SSH and TELNET services allow only 5 configurable unauthenticated connection slots. Remote attackers can exhaust these slots by making 5 concurrent unauthenticated connection attempts, causing denial of service for legitimate administrators.

MitigationImplement network-level controls such as firewall rules, ACLs, or IPSec VPNs to restrict management SSH/TELNET access to trusted IP addresses only, preventing unauthenticated connection attempts from untrusted networks.

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
Median 500l Msbr FirmwareOperating system
Affected:>= f7.20a, <= f7.20a.252.062
Median 500 Msbr FirmwareOperating system
Affected:>= f7.20a, <= f7.20a.252.062
Median M800b Msbr FirmwareOperating system
Affected:>= f7.20a, <= f7.20a.252.062
Median 800c Msbr FirmwareOperating system
Affected:>= f7.20a, <= f7.20a.252.062

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
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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. Identify the device model
    Access the device management interface or check the device label to confirm it is one of: Mediant 500L-MSBR, 500-MBSR, M800B-MSBR, or 800C-MSBR
    Affected if The device is not one of these four models, the vulnerability does not apply
  2. Check the installed firmware version
    Access the device management web interface or use the CLI command 'show system information' or 'sys get version' to retrieve the firmware version
    Affected if The firmware version is >= F7.20A and <= 7.20A.252.062 (or displays as F7.20A.252.062 or earlier within this range)
  3. Verify SSH management service is enabled
    Access the device web interface under IP > SSH Settings or use CLI command 'ssh get' to check if the SSH service is enabled for management
    Affected if SSH management service is enabled and accessible from untrusted networks
  4. Verify TELNET management service is enabled
    Access the device web interface under IP > Telnet Settings or use CLI command 'telnet get' to check if the TELNET service is enabled for management
    Affected if TELNET management service is enabled and accessible from untrusted networks
  5. Check the number of configured unauthenticated connection slots
    Access the device web interface under SSH or Telnet settings, or use CLI commands 'ssh get max-unauth' and 'telnet get max-unauth' to check the maximum concurrent unauthenticated connections setting
    Affected if The configured slot limit is 5 (the default) and the services are exposed to untrusted networks

The device is affected if it is a Mediant 500L-MSBR, 500-MBSR, M800B-MSBR, or 800C-MSBR running firmware between F7.20A and 7.20A.252.062, with SSH or TELNET management services enabled and accessible from untrusted networks.

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

Implement network-level controls such as firewall rules, ACLs, or IPSec VPNs to restrict management SSH/TELNET access to trusted IP addresses only, preventing unauthenticated connection attempts from untrusted networks.

Fix this in Median 500l Msbr Firmware Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
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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-2019-9228 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
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