CVE-2025-3899VulnerabilityPublished 10 Jun 2025

CVE-2025-3899: Schneider Electric Modicon Controllers M241/M251 · XSS or 'Cross-site Scripting'

Affects Schneider Electric Modicon Controllers M241/M251Source CVE Database V5

Not known to be exploited · CVSS 5.1 Medium : upgrade to 5.3.12.51 when convenient.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 4.0 base score

5.1Medium

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

EPSS: 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 5.3.12.51

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: Low
User Interaction: Passive
Vulnerable system confidentiality: None
Vulnerable system integrity: Low
Vulnerable system availability: None
Subsequent system confidentiality: Low
Subsequent system integrity: Low
Subsequent system availability: None

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

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, 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: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: Low: The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction: Passive: Successful exploitation of this vulnerability requires limited interaction by the targeted user with the vulnerable system and the attacker’s payload. These interactions would be considered involuntary and do not require that the user actively subvert protections built into the vulnerable system.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to the Vulnerable System.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the Subsequent System.
Subsequent system integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to the Subsequent System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 10 Jun 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 2026-10-26.

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.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC 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 Schneider Electric Modicon Controllers M241/M251 to 5.3.12.51.

Affected software

Product	Affected	Fixed in
Schneider Electric Modicon Controllers M241/M251	Affected <5.3.12.51	Fixed in 5.3.12.51

AI-suggested

To mitigate this vulnerability effectively, European organizations should: 1) Immediately identify and inventory all Modicon M241 and M251 controllers in their environment and verify firmware versions. 3) Restrict access to the web interface of these controllers by implementing network segmentation and firewall rules to limit administrative access only to trusted hosts and personnel. 4) Enforce strong authentication mechanisms and regularly rotate credentials to reduce the risk of compromised accounts. 5) Monitor web server logs and network traffic for unusual or suspicious activity indicative of attempted XSS exploitation or unauthorized access. 6) Educate users with access to these controllers about the risks of phishing and social engineering that could lead to credential compromise. 7) Consider deploying web application firewalls (WAFs) capable of detecting and blocking XSS payloads targeting the controller interfaces. 8) Conduct periodic security assessments and penetration tests focused on industrial control system web interfaces to proactively identify similar vulnerabilities.

Description

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability exists in Certificates page on Webserver that could cause an unvalidated data injected by authenticated malicious user leading to modify or read data in a victim’s browser.

Impact

For European organizations, especially those operating critical infrastructure or manufacturing facilities that utilize Schneider Electric Modicon M241/M251 controllers, this vulnerability poses a tangible risk. Successful exploitation could lead to unauthorized access or manipulation of industrial control systems via the web interface, potentially disrupting operational processes or causing safety issues. Although the vulnerability requires authenticated access, insider threats or compromised credentials could be leveraged by attackers to exploit this XSS flaw. The ability to execute scripts in the context of legitimate users may facilitate further attacks such as session hijacking, privilege escalation, or lateral movement within the network. Given the widespread use of Schneider Electric products in European industrial sectors such as energy, manufacturing, and utilities, the vulnerability could impact operational continuity and data integrity. Additionally, regulatory frameworks like NIS2 and GDPR emphasize the protection of critical infrastructure and personal data, so exploitation could also lead to compliance violations and reputational damage.

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #1OWASP Top 10 A05:2025: Injection (opens in a new tab)
The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Implementation · Architecture and Design
Understand the context in which your data will be used and the encoding that will be expected. This is especially important when transmitting data between different components, or when generating outputs that can contain multiple encodings at the same time, such as web pages or multi-part mail messages.
Architecture and Design · Implementation · Attack Surface Reduction
Understand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide…
OWASP Cheat Sheets
Cross Site Scripting Prevention (opens in a new tab)
DOM based XSS Prevention (opens in a new tab)
Injection Prevention (opens in a new tab)
Abuse Case (opens in a new tab)
Deserialization (opens in a new tab)
OWASP ASVS 4.0.3
V5.3.3 (opens in a new tab)
V1.5.1 (opens in a new tab)
Attack patterns
XSS Using MIME Type Mismatch (opens in a new tab)
DOM-Based XSS (opens in a new tab)
Reflected XSS (opens in a new tab)
Stored XSS (opens in a new tab)
Cross-Site Scripting (XSS) (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

download.schneider-electric.com/files?p_Doc_Ref=SEVD-2025-161-02&p_enDocType=Security+and+Safety+Notice&p_File_Name=SEVD-2025-161-02.pdf (opens in a new tab)

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 11 Jul 2025, 00:49 UTC

WeaknessesCWE-79

Technical details

References

Community reviews

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