CVE-2022-4876VulnerabilityPublished 4 Jan 2023Updated 28 May 2025

CVE-2022-4876: Kaltura mwEmbed · Cross Site Scripting

Affects Kaltura mwEmbedSource CVE Database V5

Not known to be exploited · CVSS 3.5 Low.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score

3.5Low

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

EPSS: 0.5% chance of exploitation in 30 days – higher than 44% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: Required
Scope: Unchanged
Confidentiality: None
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: 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: 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: None: There is no loss of confidentiality within 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 4 Jan 2023
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

AI-suggested

European organizations should prioritize upgrading Kaltura mwEmbed to version 2.96.rc2 or later to apply the official patch. If immediate upgrade is not feasible, implementing web application firewall (WAF) rules to sanitize or block suspicious HTTP_X_FORWARDED_HOST header values can reduce exposure. Additionally, organizations should conduct security awareness training to educate users about the risks of clicking unknown or suspicious links. Regular security assessments and penetration testing focusing on input validation and header manipulation can help identify similar vulnerabilities. Monitoring web server logs for unusual HTTP_X_FORWARDED_HOST header values may provide early detection of attempted exploitation. Finally, applying Content Security Policy (CSP) headers can mitigate the impact of XSS by restricting the execution of unauthorized scripts in browsers.

Description

A vulnerability was found in Kaltura mwEmbed up to 2.96.rc1 and classified as problematic. This issue affects some unknown processing of the file includes/DefaultSettings.php. The manipulation of the argument HTTP_X_FORWARDED_HOST leads to cross site scripting. The attack may be initiated remotely. Upgrading to version 2.96.rc2 is able to address this issue. The patch is named 13b8812ebc8c9fa034eed91ab35ba8423a528c0b. It is recommended to upgrade the affected component. The associated identifier of this vulnerability is VDB-217427.

Impact

For European organizations using Kaltura mwEmbed version 2.96.rc1 or earlier, this vulnerability presents a risk of client-side script injection, which can lead to session hijacking, defacement, or redirection to malicious sites. While the direct impact on server confidentiality and availability is minimal, the exploitation can undermine user trust and potentially facilitate further attacks such as phishing or credential theft. Organizations in sectors with high reliance on video content delivery, such as media, education, and corporate communications, may face reputational damage if exploited. Additionally, regulatory frameworks like GDPR emphasize protecting user data and preventing unauthorized access, so even low-severity vulnerabilities that lead to user data compromise or phishing could have compliance implications. The requirement for user interaction limits the attack vector but does not eliminate risk, especially in environments where users may be less security-aware.

Summary

CVE-2022-4876 is a cross-site scripting (XSS) vulnerability identified in Kaltura's mwEmbed component, specifically affecting versions up to 2.96.rc1. The vulnerability arises due to improper handling of the HTTP_X_FORWARDED_HOST header within the includes/DefaultSettings.php file. An attacker can manipulate this HTTP header to inject malicious scripts, which are then executed in the context of the victim's browser. This type of vulnerability is classified under CWE-79, indicating that it is a reflected or stored XSS flaw. Exploitation requires the attacker to craft a malicious HTTP request with a manipulated HTTP_X_FORWARDED_HOST header and trick a user into visiting a specially crafted URL or interacting with the affected application. The vulnerability does not require authentication but does require user interaction (e.g., clicking a link). The CVSS v3.1 base score is 3.5, reflecting a low severity primarily due to the limited impact on confidentiality and availability, and the need for user interaction. The issue has been addressed in version 2.96.rc2 of mwEmbed, with a patch identified by commit 13b8812ebc8c9fa034eed91ab35ba8423a528c0b. No known exploits have been reported in the wild to date.

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 7 Jul 2025, 09:28 UTC

WeaknessesCWE-79

Technical details

References

Community reviews

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