VulnerabilityPublished 23 Sep 2025

CVE-2025-59821: dnnsoftware Dnn.Platform · Cross-site Scripting

Affects dnnsoftware Dnn.PlatformSource CVE Database V5

Not known to be exploited · CVSS 6.5 Medium : upgrade to 10.1.0 when convenient.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score

6.5Medium

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 11% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 10.1.0

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: High
Integrity: None
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: 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: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within 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 23 Sep 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 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

Upgrade dnnsoftware Dnn.Platform to 10.1.0.

Affected software

Product	Affected	Fixed in
dnnsoftware Dnn.Platform	Affected <10.1.0	Fixed in 10.1.0

AI-suggested

European organizations should immediately assess their DNN Platform installations and identify any instances running versions earlier than 10.1.0. The primary mitigation is to upgrade all affected DNN Platform instances to version 10.1.0 or later, where the vulnerability has been patched. In parallel, organizations should implement web application firewalls (WAFs) with rules designed to detect and block reflected XSS attack patterns targeting DNN-specific URL and template parameters. Security teams should conduct thorough input validation and output encoding reviews for any custom modules or extensions integrated with DNN to ensure they do not introduce similar vulnerabilities. User awareness training should be enhanced to reduce the risk of successful phishing or social engineering attempts exploiting this vulnerability. Additionally, monitoring web server logs for unusual URL patterns or repeated suspicious requests can help detect attempted exploitation. Organizations should also review their incident response plans to quickly address any potential compromise resulting from this vulnerability.

Description

DNN (formerly DotNetNuke) is an open-source web content management platform (CMS) in the Microsoft ecosystem. Prior to version 10.1.0, DNN’s URL/path handling and template rendering can allow specially crafted input to be reflected into a user profile that is returned to the browser. In these cases, the application does not sufficiently neutralize or encode characters that are meaningful in HTML, so an attacker can cause a victim’s browser to interpret attacker-controlled content as part of the page’s HTML. This issue has been patched in version 10.1.0.

Impact

For European organizations using DNN Platform versions prior to 10.1.0, this vulnerability could lead to significant confidentiality breaches. Attackers exploiting this XSS flaw can steal session cookies, impersonate users, or deliver malicious payloads to users within the organization or its customers. This is particularly critical for organizations handling sensitive personal data or financial information, as unauthorized access could lead to data leaks or fraud. The vulnerability does not directly affect data integrity or system availability but undermines user trust and can facilitate further attacks such as phishing or malware distribution. Given the widespread use of DNN in various sectors including government, education, and enterprises across Europe, exploitation could disrupt business operations and regulatory compliance, especially under GDPR mandates for data protection. The requirement for user interaction means that social engineering or phishing campaigns could be used to maximize impact. Although no active exploitation is reported, the medium severity rating and ease of exploitation over the network without authentication make timely patching essential to mitigate risk.

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

github.com/dnnsoftware/Dnn.Platform/security/advisories/GHSA-jc4g-c8ww-5738 (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 24 Sep 2025, 00:16 UTC

WeaknessesCWE-79

Technical details

References

Community reviews

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