dbcve.org
Windows 10 1607Operating system · Microsoft

CVE-2026-35423

MEDIUM · 5.4 CVSS v3.1 Published 2026-05-12
Fix available
A fix is available. Upgrade to 10.0.14393.9140 / 10.0.17763.8755 or later.
See remediation →
61/100
Remediation priority · Elevated
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
Out-of-bounds read in Telnet Client allows an unauthorized attacker to disclose information over a network.

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

An out-of-bounds read vulnerability exists in a Telnet Client implementation, allowing an attacker to read memory beyond allocated buffers. This could enable disclosure of sensitive information such as credentials, session data, or other memory contents during Telnet communications.

MitigationReplace Telnet with SSH for remote access, as Telnet transmits data in plaintext. If Telnet use is required, apply any available vendor patches and restrict network access to trusted hosts.

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 10 1607Operating system
Affected:< 10.0.14393.9140
Windows 10 1809Operating system
Affected:< 10.0.17763.8755
Windows 10 21h2Operating system
Affected:< 10.0.19044.7291
Windows 10 22h2Operating system
Affected:< 10.0.19045.7291
Windows 11 23h2Operating system
Affected:< 10.0.22631.7079
Windows 11 24h2Operating system
Affected:< 10.0.26100.8390
Windows 11 25h2Operating system
Affected:< 10.0.26200.8390
Windows 11 26h1Operating system
Affected:< 10.0.28000.2113

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
Required
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
Low

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L

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. Check if Telnet Client is installed
    Run 'dism /online /get-features | findstr TelnetClient' in Command Prompt or check Programs and Features > Windows Features > Telnet Client
    Affected if Telnet Client feature is installed or enabled on the system
  2. Verify Windows version
    Run 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to obtain the exact Windows build number
    Affected if The installed Windows build number falls below any of these thresholds: 14393.9140, 17763.8755, 19044.7291, 19045.7291, 22631.7079, 26100.8390, 26200.8390, or 28000.2113 depending on the Windows edition and feature update version
  3. Check for Telnet usage or configuration
    Review network connection logs, check for any configured Telnet connections in remote administration tools, or examine command history for 'telnet' commands
    Affected if Telnet has been actively used or configured to connect to remote hosts
  4. Identify Telnet-related processes
    Open Task Manager or run 'tasklist | findstr telnet' to list any running Telnet client processes
    Affected if A Telnet client process is currently active or has recently been executed

The environment is affected if Telnet Client is installed and the Windows version is below the fixed build numbers for the corresponding Windows release, combined with actual or recent Telnet usage.

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 10.0.14393.9140 / 10.0.17763.8755 / 10.0.19044.7291 or later
Fixed in 10.0.14393.914010.0.17763.875510.0.19044.7291
Interim mitigation

Replace Telnet with SSH for remote access, as Telnet transmits data in plaintext. If Telnet use is required, apply any available vendor patches and restrict network access to trusted hosts.

Recommended fix Moderate confidence

Microsoft Windows Cumulative Update to the specified build number for your Windows version (e.g., 10.0.14393.9140 for Win10 1607, 10.0.17763.8755 for Win10 1809, etc.)

  1. Identify the current Windows build version by running 'winver' or 'systeminfo' in Command Prompt
  2. Determine which Windows version and build you are running from the list of affected versions
  3. For Windows 10 1607: upgrade to build 10.0.14393.9140 or later
  4. For Windows 10 1809: upgrade to build 10.0.17763.8755 or later
  5. For Windows 10 21h2: upgrade to build 10.0.19044.7291 or later
  6. For Windows 10 22h2: upgrade to build 10.0.19045.7291 or later
  7. For Windows 11 23h2: upgrade to build 10.0.22631.7079 or later
  8. For Windows 11 24h2: upgrade to build 10.0.26100.8390 or later
Caveat Standard Windows update; minimal risk. Ensure regular backups before applying updates in production environments.

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

Fix this in Windows 10 1607 Scoped from the published advisory
  • Consultation2.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
16.0 hours of engineering $2,800
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,480.

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-2026-35423 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