VulnerabilityPublished 18 Mar 2026

CVE-2026-22316: Phoenix Contact FL SWITCH 2005 · Stack-based Buffer Overflow

Affects Phoenix Contact FL SWITCH 2005Source CVE Database V5

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Not known to be exploited · CVSS 6.5 Medium : upgrade to 3.53 when convenient.

Data as of 30 Oct 2026, 20:25 UTC

CVSS 3.1 base score

6.5Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.3% chance of exploitation in 30 days – higher than 33% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 3.53

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 18 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade FL to 3.53.

Affected software

Product	Affected	Fixed in
Phoenix ContactFL SWITCH 2005	Affected <3.53	Fixed in 3.53
Phoenix ContactFL SWITCH 2008	Affected <3.53	Fixed in 3.53
Phoenix ContactFL SWITCH 2016	Affected <3.53	Fixed in 3.53
Phoenix ContactFL SWITCH 2105	Affected <3.53	Fixed in 3.53
Phoenix ContactFL SWITCH 2108	Affected <3.53	Fixed in 3.53
Phoenix ContactFL SWITCH 2116	Affected <3.53	Fixed in 3.53

AI-suggested

To mitigate CVE-2026-22316 effectively, organizations should implement the following specific measures: 1) Restrict access to the FL SWITCH 2005 webUI strictly to trusted administrators via network segmentation and firewall rules, minimizing exposure to untrusted networks. 2) Enforce strong authentication mechanisms and credential management to prevent unauthorized user-level access. 3) Monitor network traffic for unusual POST requests targeting the TFTP Filename parameter or other suspicious webUI activity indicative of exploitation attempts. 4) Employ intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics tuned to detect buffer overflow attempts against the device. 5) Maintain an inventory of all Phoenix Contact FL SWITCH 2005 devices and prioritize patching or firmware updates as soon as vendors release fixes. 6) Consider deploying redundant network paths or failover mechanisms to maintain availability if a device becomes unresponsive. 7) Engage with Phoenix Contact support channels to obtain security advisories and updates. 8) Conduct regular security audits and penetration testing focused on industrial network devices to identify and remediate similar vulnerabilities proactively.

Description

A remote attacker with user privileges for the webUI can use the setting of the TFTP Filename with a POST Request to trigger a stack-based Buffer Overflow, resulting in a DoS attack.

Impact

The primary impact of CVE-2026-22316 is denial of service (DoS) against Phoenix Contact FL SWITCH 2005 devices. An attacker with user-level access to the webUI can cause the device to crash or become unresponsive by exploiting the buffer overflow. This can disrupt network connectivity, affecting industrial control systems, manufacturing processes, or other critical infrastructure relying on these switches. Although the vulnerability does not compromise confidentiality or integrity, the loss of availability can lead to operational downtime, safety risks in industrial environments, and potential financial losses. The requirement for authenticated access limits the attack surface, but insider threats or compromised credentials could enable exploitation. The absence of known exploits reduces immediate risk, but the medium severity score indicates a meaningful threat if leveraged in targeted attacks. Organizations with large deployments of these switches may experience significant operational impact if multiple devices are affected simultaneously.

CWE-121Stack-based Buffer Overflow (opens in a new tab)
Variant weaknessLikelihood of exploit: HighCWE Top 25 (2025): #14
The product writes past the end of a buffer that was allocated on the stack.
Operation · Build and Compilation · Environment Hardening
Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index…
Architecture and Design
Use an abstraction library to abstract away risky APIs. Not a complete solution.
Implementation
Implement and perform bounds checking on input.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

certvde.com/de/advisories/VDE-2025-104 (opens in a new tab)

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 18 Mar 2026, 07:59 UTC

WeaknessesCWE-121

Technical details

References

Community reviews

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