CVE-2025-59839VulnerabilityPublished 25 Sep 2025

CVE-2025-59839: StarCitizenWiki mediawiki-extensions-EmbedVideo · Cross-site Scripting

Affects StarCitizenWiki mediawiki-extensions-EmbedVideoSource CVE Database V5

Not known to be exploited · CVSS 8.6 High.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

8.6High

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 23% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

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

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: 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: 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: 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: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 25 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 2026-10-25.

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

Affected software

Product	Affected	Fixed in
StarCitizenWiki mediawiki-extensions-EmbedVideo	Affected <=4.0.0	Fixed in–

AI-suggested

European organizations should immediately audit their MediaWiki installations to identify the presence and version of the EmbedVideo extension. If version 4.0.0 or earlier is in use, an urgent upgrade to the patched version should be performed. If an upgrade is not immediately feasible, organizations should consider disabling the EmbedVideo extension temporarily to eliminate the attack vector. Implement strict input validation and output encoding policies on wiki content, especially for user-generated content that can include HTML attributes. Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts in browsers. Regularly monitor wiki pages for suspicious content or unexpected attribute injections. Additionally, enforce least privilege principles for wiki users, limiting editing rights to trusted personnel to reduce the risk of malicious content insertion. Conduct security awareness training for wiki administrators and users to recognize and report suspicious behavior. Finally, keep MediaWiki and all extensions up to date with security patches to mitigate similar vulnerabilities.

Description

The EmbedVideo Extension is a MediaWiki extension which adds a parser function called #ev and various parser tags for embedding video clips from various video sharing services. In versions 4.0.0 and prior, the EmbedVideo extension allows adding arbitrary attributes to an HTML element, allowing for stored XSS through wikitext. This issue has been patched via commit 4e075d3.

Impact

For European organizations, this vulnerability poses a substantial risk, especially for those operating public-facing or internal MediaWiki-based knowledge bases or documentation portals that utilize the EmbedVideo extension. Exploitation could lead to unauthorized access to sensitive information, including user credentials and internal documentation, through session hijacking or theft of authentication tokens. The stored XSS can also be leveraged to perform actions on behalf of authenticated users, potentially leading to privilege escalation or data manipulation. Organizations in sectors such as government, finance, healthcare, and critical infrastructure, which often rely on MediaWiki for collaborative documentation, could face reputational damage, regulatory penalties under GDPR for data breaches, and operational disruptions. The vulnerability's ability to be exploited without authentication increases the attack surface, making it easier for attackers to compromise systems remotely. Additionally, the presence of embedded video content is common in modern documentation, increasing the likelihood of this extension's deployment and thus the exposure 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

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 25 Sep 2025, 14:26 UTC

WeaknessesCWE-79

Technical details

References

Community reviews

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