CVE-2021-25253
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 · uneditedAn improper access control vulnerability in Trend Micro Apex One, Trend Micro Apex One as a Service and OfficeScan XG SP1 on a resource used by the service could allow a local attacker to escalate privileges on affected installations. Please note: an attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability.
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 confidenceAn improper access control vulnerability in Trend Micro Apex One, Apex One as a Service, and OfficeScan XG SP1 allows a local attacker who can first execute low-privileged code to escalate privileges by exploiting a resource used by the service.
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= 2019= xgCVSS 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
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/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 checksWork through these to decide whether this CVE applies to you.
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Identify installed Trend Micro productCheck installed programs or services for 'Apex One' or 'OfficeScan' - look for service names like 'Apex One', 'OfficeScan', or 'TmServ' in Windows Services or process listAffected if Neither Apex One nor OfficeScan is installed, then not affected
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Confirm product versionCheck the installed version of Apex One 2019 or OfficeScan XG - typically found in the product UI under 'About' or in Windows Programs and FeaturesAffected if Version is not Apex One 2019 or OfficeScan XG, then not affected
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Verify service is runningCheck if the Apex One/OfficeScan service is actively running - open Services.msc and look for 'Trend Micro Apex One Security Agent' or 'OfficeScan NT Listener' service, or run 'sc query' for these servicesAffected if The service is not running, the vulnerable resource is not in use and exploitation is not possible
Affected if Apex One 2019 or OfficeScan XG is installed with the service actively running, allowing a local low-privileged attacker to escalate privileges via the vulnerable service resource.
Generated from the published advisory. Verify against your own configuration.
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 dataApply vendor-supplied patches or updates for Trend Micro Apex One/OfficeScan to remediate the improper access control vulnerability.
- Consultation2.0 h
- Implementation4.0 h
- Testing6.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,808.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-25253 — 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 sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-25253 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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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.
- 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