CVE-2026-22321: phoenix contact fl nat 2008 Stack-based Buffer Overflow

Vulnerability summary

CVE-2026-22321 is a medium (CVSS 5.3) Stack-based Buffer Overflow vulnerability in phoenix contact fl nat 2008. EPSS estimates a 0.38% chance of exploitation in the next 30 days, higher than 30.5% of scored vulnerabilities.

Timeline

1. 18-03-2026
   PublishedVulnerability first disclosed.
2. 18-03-2026
   Last modifiedVulnerability information updated.

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.

• CWE-121Stack-based Buffer OverflowA 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).