Windows Server 2025Operating system · Microsoft

CVE-2026-20830

HIGH · 7.0 CVSS v3.1 Published 2026-01-13
Fix available
A fix is available. Upgrade to 10.0.26100.7623 or later.
See remediation →
72/100
Remediation priority · Elevated
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
Concurrent execution using shared resource with improper synchronization ('race condition') in Capability Access Management Service (camsvc) allows an authorized attacker to elevate privileges locally.

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 race condition vulnerability exists in the Windows Capability Access Management Service (camsvc) where improper synchronization of shared resources allows an authorized local attacker to exploit concurrent execution and elevate privileges to higher integrity levels.

MitigationApply the vendor patch when available; in the interim, limit local access to the system and monitor for suspicious processes interacting with the camsvc 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
Windows Server 2025Operating system
Affected:< 10.0.26100.7623

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
Local
Complexity
High
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:H/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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify the Windows Server version
    Run 'winver' or 'systeminfo' to confirm the installed Windows version and build number
    Affected if The system is running Microsoft Windows Server 2025 with a build lower than 10.0.26100.7623
  2. Verify camsvc service presence
    Check if the Capability Access Management Service exists by running 'sc query camsvc' or viewing Services.msc
    Affected if The camsvc service is present on the system (this is the vulnerable component)
  3. Confirm the exact OS build number
    Run 'winver' or 'ver' command and note the full version string (e.g., 10.0.26100.xxxx)
    Affected if The build number is below 10.0.26100.7623 - compare your version against this threshold
  4. Audit privileged account assignments
    Review Security Event Log for Event ID 4672 (Special privileges assigned to new logon) or use 'whoami /priv' to check current user privileges
    Affected if Unexpected privilege escalation events occur or unusual accounts hold elevated privileges post-logon
  5. Monitor for camsvc interaction
    Use Process Monitor (procmon) or Windows Event Logging to observe which processes access the camsvc service, check for concurrent access patterns
    Affected if Multiple processes or suspicious threads are observed interacting with camsvc simultaneously

A system is affected if it runs Windows Server 2025 with build version lower than 10.0.26100.7623 and has the camsvc service present and accessible.

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
Upgrade available Upgrade to 10.0.26100.7623 or later
Fixed in 10.0.26100.7623
Interim mitigation

Apply the vendor patch when available; in the interim, limit local access to the system and monitor for suspicious processes interacting with the camsvc service.

Recommended fix High confidence

Windows Server 2025 build 10.0.26100.7623 or later

  1. Identify current Windows Server 2025 build version by running 'winver' or 'systeminfo' in Command Prompt
  2. Navigate to Windows Update settings or check Microsoft Update Catalog
  3. Search for and install the security update containing build 10.0.26100.7623 or later
  4. Alternatively, download the specific security update from Microsoft Update Catalog using KB number from the corresponding MSRC release
  5. Restart the server after applying the update
  6. Verify the installed build version matches or exceeds 10.0.26100.7623 using 'winver'
Caveat Standard Windows Server update - review release notes for any configuration changes or known issues before deploying in production

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

Fix this in Windows Server 2025 Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA3.0 h
15.0 hours of engineering $2,560
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,096.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-20830 — 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-2026-20830 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