5.3
MEDIUM
CVSS 3.1
CVE-2026-22321
Stack-Based Buffer Overflow in CLI Login Username Handling over CLI
Overview
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.
Details
INFO
Published Date :
March 18, 2026, 8:16 a.m.
Last Modified :
June 17, 2026, 10:19 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Impact
Affected Products
The following products are affected by CVE-2026-22321
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
Scoring
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework
for assessing the severity of vulnerabilities in software and systems.
We collect and displays CVSS scores from various sources for each CVE.
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | 270ccfa6-a436-4e77-922e-914ec3a9685c | ||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
Address stack-based buffer overflow in CLI login by validating username input length.
- Validate username input length.
- Apply vendor-provided security patches.
- Update the device firmware.
- Restrict Telnet/SSH access.
References
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-22321.
| URL | Resource |
|---|---|
| https://certvde.com/de/advisories/VDE-2025-104 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-22321 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-22321
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-22321 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-22321 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by [email protected]
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2005', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2008', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2016', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2105', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2108', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2116', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2204-2TC-2SFX', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2205', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2206-2FX', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2206-2FX SM', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2206-2FX SM ST', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2206-2FX ST', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2206-2SFX', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2206-2SFX PN', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2206C-2FX', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2207-FX', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2207-FX SM', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2208', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2208 PN', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2208C', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2212-2TC-2SFX', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2214-2FX', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2214-2FX SM', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2214-2SFX', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2214-2SFX PN', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2216', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2216 PN', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2304-2GC-2SFP', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2306-2SFP', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2306-2SFP PN', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2308', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2308 PN', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2312-2GC-2SFP', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2314-2SFP', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2314-2SFP PN', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2316', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2316 PN', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2404-2TC-2SFX', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2406-2SFX', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2406-2SFX PN', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2408', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2408 PN', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2412-2TC-2SFX', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2414-2SFX', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2414-2SFX PN', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2416', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2416 PN', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2504-2GC-2SFP', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2506-2SFP', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2506-2SFP PN', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2508', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2508 PN', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2512-2GC-2SFP', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2514-2SFP', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2514-2SFP PN', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2516', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2516 PN', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2608', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2608 PN', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2708', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2708 PN', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2303-8SP1', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL NAT 2008', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL NAT 2208', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL NAT 2304-2GC-2SFP', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2008F', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2316/K1', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2506-2SFP/K1', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 2508/K1', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH TSN 2316', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH TSN 2312-2GC-2SFP', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH TSN 2314-2SFP', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 5924-4GC', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 5916-8GC-4SFP+', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 5924SFP-4GC', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 5924-4SFP+', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}, {'vendor': 'Phoenix Contact', 'product': 'FL SWITCH 5916SFP-8GC-4SFP+', 'versions': [{'status': 'affected', 'version': '0.0.0', 'lessThan': '3.53', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-22321', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-03-18T13:32:15.348977Z'} -
New CVE Received by [email protected]
Mar. 18, 2026
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L Added CWE CWE-121 Added Reference https://certvde.com/de/advisories/VDE-2025-104
EPSS is a daily estimate of the probability of exploitation activity
being observed over the next 30 days. Following chart shows the EPSS
score history of the vulnerability.