CVE-2026-22321
Received Received - Intake
Stack-Based Buffer Overflow in Telnet/SSH CLI Causes Session Crash

Publication date: 2026-03-18

Last updated on: 2026-03-18

Assigner: CERT VDE

Description
A stack-based buffer overflow in the device's Telnet/SSH CLI login routine occurs when a unauthenticated attacker send an oversized or unexpected username input. An overflow condition crashes the thread handling the login attempt, forcing the session to close. Because other CLI sessions remain unaffected, the impact is limited to a low‑severity availability disruption.
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Meta Information
Published
2026-03-18
Last Modified
2026-03-18
Generated
2026-06-16
AI Q&A
2026-03-18
EPSS Evaluated
2026-06-15
NVD
CVE-2026-22321
EUVD
EUVD-2026-12790
Affected Vendors & Products
Showing 2 associated CPEs
Vendor Product Version / Range
phoenix_contact fl_switch to 3.53 (exc)
phoenix_contact fl_switch 3.53
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-121 A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).
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Executive Summary

This vulnerability is a stack-based buffer overflow in the device's Telnet/SSH CLI login routine. It occurs when an unauthenticated attacker sends an oversized or unexpected username input. This overflow causes the thread handling the login attempt to crash, which forces the session to close.

Impact Analysis

The impact of this vulnerability is limited to a low-severity availability disruption. Specifically, the overflow condition crashes the login attempt thread and closes that session, but other CLI sessions remain unaffected.

Compliance Impact

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