Stack-based Buffer OverflowWeakness · CWE-121

CVE-2025-41687

CRITICAL · 9.8 CVSS v3.1 Published 2025-07-23
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
An unauthenticated remote attacker may use a stack based buffer overflow in the u-link Management API to gain full access on the affected devices.

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

A stack-based buffer overflow vulnerability exists in the u-link Management API that allows unauthenticated remote attackers to overflow a stack buffer and gain full administrative access to affected devices.

MitigationApply vendor-provided patches for the u-link Management API. If no patch exists, implement input validation and bounds checking on API parameters, or restrict network access to the Management API.

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
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 if u-link Management API is running
    Check for processes or services related to 'u-link' or 'Management API' running on the system. Review network listening services on common management ports (443, 8080, 8443) or any service responding to /api/ management endpoints.
    Affected if The u-link Management API service is running and exposed on the system.
  2. Determine API version
    Query the Management API version endpoint if available (commonly /api/version, /api/status, or check HTTP response headers). Consult system inventory or software documentation for the installed u-link Management API version.
    Affected if The installed version matches or falls within any affected version range published by the vendor (check vendor advisory for specific version numbers).
  3. Verify API accessibility
    Attempt to access the Management API endpoint without credentials from an external system. Check if HTTP/HTTPS management interfaces accept requests without requiring authentication.
    Affected if The Management API accepts unauthenticated requests from network attackers.
  4. Check network exposure
    Review firewall rules, ACLs, and network segmentation configurations to determine if the Management API is accessible from untrusted networks or the internet.
    Affected if The Management API is reachable from untrusted network segments or the internet.
  5. Inspect API configuration
    Review API configuration files or settings for authentication enforcement, disabled security features, or permitted anonymous access settings.
    Affected if Authentication is disabled or not enforced for the Management API endpoints.

The environment is affected if the u-link Management API is running, is network-accessible, and accepts unauthenticated requests, particularly if the version matches vendor-affected ranges.

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-provided patches for the u-link Management API. If no patch exists, implement input validation and bounds checking on API parameters, or restrict network access to the Management API.

Have this fixed Scoped from the published advisory
  • Consultation3.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA3.0 h
20.0 hours of engineering $3,480
Get help mitigating

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Scan for this in your stack

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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-2025-41687 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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