Univerge Sv9500 FirmwareOperating system · Nec

CVE-2020-5685

CRITICAL · 9.8 CVSS v3.1 Published 2021-01-13
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
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
UNIVERGE SV9500 series from V1 to V7and SV8500 series from S6 to S8 allows an attacker to execute arbitrary OS commands or cause a denial-of-service (DoS) condition by sending a specially crafted request to a specific URL.

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 · high confidence

A critical command injection vulnerability in NEC UNIVERGE SV9500 (V1-V7) and SV8500 (S6-S8) series phone systems allows unauthenticated attackers to execute arbitrary OS commands or cause denial of service by sending specially crafted requests to a specific URL endpoint.

MitigationApply vendor patches immediately if available; if no patch exists, implement strict network access controls, isolate affected systems behind firewalls, and block the vulnerable URL at the network perimeter to prevent external 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
Univerge Sv9500 FirmwareOperating system
Affected:>= v1, <= v7
Univerge Sv8500 FirmwareOperating system
Affected:>= s6, <= s8

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
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/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. Identify NEC UNIVERGE model
    Determine whether the phone system is an SV9500 or SV8500 series by checking the device label, admin interface, or firmware metadata
    Affected if The device is a NEC UNIVERGE SV9500 or SV8500 series phone system
  2. Check SV9500 firmware version
    Access the device admin console or system information page and locate the firmware version. Compare it against the affected range V1 through V7
    Affected if SV9500 firmware version is between V1 and V7 inclusive
  3. Check SV8500 firmware version
    Access the device admin console or system information page and locate the firmware version. Compare it against the affected range S6 through S8
    Affected if SV8500 firmware version is between S6 and S8 inclusive
  4. Verify network accessibility of vulnerable endpoint
    Review network configuration, firewall rules, and perimeter ACLs to determine if the specific URL endpoint associated with this vulnerability is reachable from untrusted networks
    Affected if The vulnerable URL endpoint is exposed to external or untrusted networks without authentication

The environment is affected if it runs a NEC UNIVERGE SV9500 (V1-V7) or SV8500 (S6-S8) with the vulnerable endpoint accessible from the network.

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 vendor patches immediately if available; if no patch exists, implement strict network access controls, isolate affected systems behind firewalls, and block the vulnerable URL at the network perimeter to prevent external exploitation.

Fix this in Univerge Sv9500 Firmware Scoped from the published advisory
  • Consultation6.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA3.0 h
21.0 hours of engineering $3,780
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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2020-5685 — 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 sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2020-5685 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