Windows 11 Telnet Client Information Disclosure Vulnerability
CVE-2026-35423 is an information disclosure vulnerability in the Windows 11 Telnet Client. According to the provided Microsoft advisory context, the flaw is caused by an out-of-bounds read when the Telnet client processes specially crafted authentication responses from a remote server. If triggered, the client may read memory outside the intended bounds and disclose limited sensitive information from system memory associated with data being processed by the Telnet client during the connection.
Are you exposed to this one?
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Impact, mitigation & remediation
What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.
Impact
What an attacker gets, and what they’ve been doing with it.
Mitigation
If you can’t patch tonight, do this now.
Remediation
Patch, then assume compromise.
Exploits
No public exploits tracked yet. Mallory keeps watching.
No public exploit code observed for this vulnerability.
Affected products & vendors
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
3 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A Windows 11 Telnet Client information disclosure vulnerability.
An information disclosure vulnerability affecting the Windows 11 Telnet Client.
An information disclosure vulnerability in the Windows 11 Telnet Client caused by an out-of-bounds read, allowing an unauthorized attacker to disclose limited sensitive information over a network when a user initiates a Telnet connection to a malicious or compromised server.
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.