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Deserialization of Untrusted DataWeakness · CWE-502

CVE-2026-21665

HIGH · 7.7 CVSS v4.0 Published 2026-02-23
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

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 Print Service component of Fiserv Originate Loans Peripherals (formerly Velocity Services) in unsupported version 2021.2.4 (build 4.7.3155.0011) uses deprecated .NET Remoting TCP channels that allow unsafe deserialization of untrusted data. When these services are exposed to an untrusted network in a client-managed deployment, an unauthenticated attacker can achieve remote code execution. Version 2021.2.4 is no longer supported by Fiserv. Customers should upgrade to a currently supported release (2025.1 or later) and ensure that .NET Remoting service ports are not exposed beyond trusted network boundaries. This CVE documents behavior observed in a client-hosted deployment running an unsupported legacy version of Originate Loans Peripherals with .NET Remoting ports exposed to an untrusted network. This is not a default or supported configuration. Customers running legacy versions should upgrade to a currently supported release and ensure .NET Remoting ports are restricted to trusted network segments. The finding does not apply to Fiserv-hosted environments.

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

The Print Service component in unsupported Fiserv Originate Loans Peripherals v2021.2.4 uses deprecated .NET Remoting TCP channels with unsafe deserialization. When exposed to untrusted networks in client-managed deployments, unauthenticated attackers can achieve remote code execution via deserialization attacks.

MitigationUpgrade to supported release (2025.1 or later) and ensure .NET Remoting service ports are restricted to trusted network segments; this finding does not apply to Fiserv-hosted environments.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

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
Authentication
X
User interaction
P
Scope
X

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

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 Fiserv Originate Loans Peripherals installation
    Locate the Print Service component installation directory or installed programs list on the system
    Affected if The software named 'Fiserv Originate Loans Peripherals' with Print Service component is found
  2. Check installed version
    Inspect the version information of the Print Service or parent Originate Loans Peripherals installation using installed programs list, executable version info, or configuration files
    Affected if The version is 2021.2.4 or an earlier unsupported version in the 2021.x line
  3. Verify client-managed deployment type
    Confirm whether this is a client-managed (on-premise/self-hosted) deployment rather than a Fiserv-hosted cloud service
    Affected if The deployment is client-managed or self-hosted on premise
  4. Confirm Print Service component is enabled
    Check if the Print Service component is running or configured to run as part of the Fiserv deployment
    Affected if The Print Service component is installed and enabled
  5. Check .NET Remoting exposure
    Inspect network configuration, firewall rules, or service bindings to determine if .NET Remoting TCP channels are listening on accessible network interfaces
    Affected if NET Remoting ports are bound to network interfaces accessible from untrusted or external networks

User is affected if they run client-managed Fiserv Originate Loans Peripherals v2021.2.4 or earlier with the Print Service enabled and .NET Remoting exposed to 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.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade to supported release (2025.1 or later) and ensure .NET Remoting service ports are restricted to trusted network segments; this finding does not apply to Fiserv-hosted environments.

Recommended fix High confidence

2025.1 or later

  1. Upgrade Fiserv Originate Loans Peripherals from version 2021.2.4 to version 2025.1 or later (currently supported release)
  2. Ensure .NET Remoting service ports are not exposed beyond trusted network boundaries
  3. Verify the upgrade in a test environment before deploying to production

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

Have this fixed Scoped from the published advisory
  • Consultation8.0 h
  • Implementation24.0 h
  • Testing16.0 h
  • Review / QA8.0 h
56.0 hours of engineering $9,760
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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-2026-21665 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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  • No spam, self-promotion, credentials, or personal data