VulnerabilityPublished 14 Jan 2026

CVE-2025-67833: Paessler PRTG Network Monitor · Cross-site Scripting

Source CVE Database V5

Not known to be exploited · CVSS 6.1 Medium · fixed in 25.4.114 : update Paessler PRTG Network Monitor when convenient.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score

6.1Medium

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 18% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Affects: Paessler PRTG Network Monitor before 25.4.114
Patch: Available – fixed in 25.4.114

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

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

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: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
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 impacted component.
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 on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 14 Jan 2026
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 26 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.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, 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

AI-suggested

European organizations should immediately verify their PRTG Network Monitor version and plan to upgrade to version 25.4.114 or later once available. In the absence of an official patch, implement strict input validation and sanitization on the 'tag' parameter if custom integrations or proxies are used. Deploy Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts in browsers accessing the PRTG interface. Educate users, especially network administrators, about the risks of clicking on suspicious links and implement email filtering to reduce phishing attempts. Monitor web server logs and application logs for unusual requests containing suspicious 'tag' parameter values. Consider isolating the PRTG interface behind VPNs or access control lists to limit exposure to unauthenticated external users. Regularly review and update incident response plans to include scenarios involving web interface compromises.

Description

CVE-2025-67833 is a medium severity cross-site scripting (XSS) vulnerability in Paessler PRTG Network Monitor versions before 25.4.114. It allows unauthenticated attackers to inject malicious scripts via the 'tag' parameter, potentially leading to session hijacking or user impersonation. Exploitation requires user interaction but no authentication, and the vulnerability impacts confidentiality and integrity without affecting availability. No known exploits are currently reported in the wild. European organizations using vulnerable PRTG versions should prioritize patching once available and implement input validation and content security policies to mitigate risk. Countries with high adoption of PRTG and critical infrastructure monitoring are at greater risk. Due to the scope and ease of exploitation, the severity is rated medium. Defenders should monitor for suspicious activity and educate users about phishing attempts leveraging this flaw.

Impact

For European organizations, this vulnerability poses a risk primarily to the confidentiality and integrity of monitoring data and user sessions within PRTG Network Monitor environments. Successful exploitation could allow attackers to hijack sessions of network administrators or users with access to the monitoring dashboard, potentially enabling unauthorized viewing or manipulation of network status information. This could lead to delayed detection of network issues or misinformed operational decisions. While availability is not directly impacted, the indirect effects on network security posture could be significant, especially in critical infrastructure sectors such as energy, finance, and telecommunications. The requirement for user interaction limits mass exploitation but targeted phishing campaigns could be effective. Organizations relying heavily on PRTG for real-time monitoring should be particularly vigilant, as compromised monitoring tools can serve as a foothold for lateral movement within internal networks.

Summary

CVE-2025-67833 is a cross-site scripting (XSS) vulnerability identified in Paessler PRTG Network Monitor prior to version 25.4.114. The vulnerability arises from insufficient sanitization of the 'tag' parameter, which is accessible without authentication. An attacker can craft a malicious URL containing a specially crafted 'tag' parameter that, when visited by a legitimate user, executes arbitrary JavaScript in the context of the victim's browser session. This can lead to theft of session cookies, unauthorized actions performed on behalf of the user, or redirection to malicious sites. The vulnerability is classified under CWE-79, indicating improper neutralization of input during web page generation. The CVSS v3.1 base score is 6.1, reflecting network attack vector, low attack complexity, no privileges required, but requiring user interaction, and a scope change with partial impact on confidentiality and integrity but no impact on availability. No patches are currently linked, and no known exploits have been reported in the wild as of the publication date. The vulnerability affects all versions before 25.4.114, though exact affected versions are not specified. Given PRTG's role in network monitoring, exploitation could undermine trust in monitoring data or facilitate further attacks within the network.

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

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 21 Jan 2026, 20:47 UTC

WeaknessesCWE-79

Technical details

References

Community reviews

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