CVE-2026-20868
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 · uneditedHeap-based buffer overflow in Windows Routing and Remote Access Service (RRAS) allows an unauthorized attacker to execute code over a network.
In the news
Third-party coverage- Microsoft January 2026 Patch Tuesday fixes 3 zero-days, 114 flaws
- Microsoft CVE Summary - Bleeping Computer
Surfaced from public web coverage — external links open in a new tab.
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 confidenceHeap-based buffer overflow vulnerability in Windows Routing and Remote Access Service (RRAS) allows an unauthenticated remote attacker to execute arbitrary code by sending specially crafted network packets to the RRAS 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< 10.0.14393.8783< 10.0.17763.8276< 10.0.19044.6809< 10.0.19045.6809< 10.0.22631.6491< 10.0.26100.7623< 10.0.26200.7623all versions= r2CVSS 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
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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.
-
Verify RRAS installation statusOpen Server Manager > Add Roles and Features, or run 'Get-WindowsFeature -Name Routing' in PowerShell on Server; on client Windows, check Services console (services.msc) for 'Routing and Remote Access' service existenceAffected if RRAS is installed and the service exists on the system
-
Confirm RRAS service is runningRun 'Get-Service RemoteAccess' in PowerShell or check the RemoteAccess service status in services.mscAffected if The RemoteAccess service is started or running (even if set to Manual)
-
Identify installed Windows versionRun 'winver' from Run dialog, or execute 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' in Command Prompt, or use PowerShell '[System.Environment]::OSVersion.Version'Affected if The Windows version falls within any of the affected ranges: Windows 10 1607 (<10.0.14393.8783), 1809 (<10.0.17763.8276), 21h2 (<10.0.19044.6809), 22h2 (<10.0.19045.6809); Windows 11 23h2 (<10.0.22631.6491), 24h2 (<10.0.26100.7623), 25h2 (<10.0.26200.7623); or Windows Server 2008/2008 R2 (all versio
-
Confirm RRAS network exposureCheck firewall rules and port listening status: run 'netsh routing ip show status' or use 'netstat -an | findstr 1723' (PPTP) and check for GRE protocol (47) listening, or review RRAS configuration in Routing and Remote Access snap-in (rrasmgmt.msc)Affected if RRAS ports/protocols (PPTP port 1723, GRE protocol 47, or IKE port 500) are exposed to untrusted networks or listening on external interfaces
You are affected if RRAS is installed/enabled on a Windows version within the affected version ranges and the system is vulnerable based on its unpatched version number.
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.
dbcve · scoped10.0.14393.878310.0.17763.827610.0.19044.6809
Apply vendor patches when released; if unavailable, disable RRAS if not required, or restrict network access to RRAS ports using firewalls/ACLs to limit exposure to trusted networks.
Upgrade to the specific cumulative update build for your Windows version: Windows 10 1607 to 10.0.14393.8783+, Windows 10 1809 to 10.0.17763.8276+, Windows 10 21h2 to 10.0.19044.6809+, Windows 10 22h2 to 10.0.19045.6809+, Windows 11 23h2 to 10.0.22631.6491+, Windows 11 24h2 to 10.0.26100.7623+, Wind
- Identify the current Windows version and build number by running 'winver' or 'systeminfo'
- For Windows 10 1607: Upgrade to Windows 10 build 10.0.14393.8783 or later
- For Windows 10 1809: Upgrade to Windows 10 build 10.0.17763.8276 or later
- For Windows 10 21h2: Upgrade to Windows 10 build 10.0.19044.6809 or later
- For Windows 10 22h2: Upgrade to Windows 10 build 10.0.19045.6809 or later
- For Windows 11 23h2: Upgrade to Windows 11 build 10.0.22631.6491 or later
- For Windows 11 24h2: Upgrade to Windows 11 build 10.0.26100.7623 or later
- For Windows 11 25h2: Upgrade to Windows 11 build 10.0.26200.7623 or later
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation4.0 h
- Testing4.0 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 $3,648.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-20868 — 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-2026-20868 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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