3cxApplication

CVE-2021-45490

CRITICAL · 9.1 CVSS v3.1 Published 2022-03-28
Fix available
A fix is available. Upgrade to after 2022-03-17 or later.
See remediation →
100/100
Remediation priority · Urgent
Public exploit 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
The client applications in 3CX on Windows, the 3CX app for iOS, and the 3CX application for Android through 2022-03-17 lack SSL certificate validation.

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
How this class of weakness works · CWE-295

The application does not properly validate the TLS certificate presented by the other side — skipping the chain, the hostname, or expiry — so an attacker with a forged or mismatched certificate can sit in the middle of a supposedly secure connection. It is a common trap in custom clients and misconfigured libraries. The fix is full certificate validation, and never disabling verification to make errors go away.

General guidance for the improper certificate validation class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

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
3cxApplication
Affected:<= 18.0.4<= 18.0.11<= 2022-03-17

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
None

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

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.

dbcve · scoped
Upgrade available Upgrade to a release after 2022-03-17
Recommended fix Moderate confidence

3CX client versions released after 2022-03-17 that include SSL certificate validation fixes

  1. 1. Identify the current 3CX client version installed on Windows, iOS, or Android devices
  2. 2. Download the latest 3CX client application from the official 3CX website (www.3cx.com) or your organization's approved software distribution channel
  3. 3. Uninstall the existing 3CX client from affected devices
  4. 4. Install the latest 3CX client version that includes proper SSL certificate validation
  5. 5. Verify the update was successful by checking the client version information
Caveat Review 3CX release notes for any breaking changes between your current version and the target version, particularly regarding server compatibility and feature changes

Generated from the published advisory — verify against the referenced sources before acting.

We can identify the exact fixed release, upgrade, and verify it in staging — typical engagement from $2,300. Get the upgrade done

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2021-45490 — 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-2021-45490 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