CVE-2025-22388VulnerabilityPublished 4 Jan 2025Updated 6 Jan 2025

CVE-2025-22388: episerver.cms.core · XSS or 'Cross-site Scripting'

Affects episerver.cms.coreSource CVE Database V5

Not known to be exploited · CVSS 5.7 Medium : upgrade to 12.22.0 when convenient.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score

5.7Medium

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 30% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 12.22.0

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
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: 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: 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 4 Jan 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 Optimizely/episerver.cms.core to 12.22.0.

Affected software

Product	Affected	Fixed in
NuGetOptimizely/episerver.cms.core`pkg:nuget/Optimizely/episerver.cms.core`Other threats	Affected <12.22.0	Fixed in 12.22.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

1. Upgrade Optimizely EPiServer.CMS.Core to version 12.22.0 or later as soon as the patch is available to fully remediate the vulnerability. 2. Implement strict input validation on all user-supplied data in content editing, link management, and file upload modules to reject or sanitize potentially malicious scripts. 3. Apply context-aware output encoding (e.g., HTML entity encoding) to all dynamic content rendered in web pages to prevent script execution. 4. Enforce the principle of least privilege by limiting user permissions to only those necessary for their roles, reducing the risk of exploitation by low-privilege users. 5. Monitor CMS logs and user activities for unusual behavior indicative of XSS attempts or successful exploitation. 6. Educate content editors and administrators about the risks of injecting untrusted content and encourage cautious handling of user inputs. 7. Consider deploying Web Application Firewalls (WAFs) with rules targeting common XSS attack patterns as an additional layer of defense. 8. Regularly review and update security policies and conduct penetration testing focused on XSS vulnerabilities in CMS environments.

Description

An issue was discovered in Optimizely EPiServer.CMS.Core before 12.22.0. A high-severity Stored Cross-Site Scripting (XSS) vulnerability exists in the CMS, allowing malicious actors to inject and execute arbitrary JavaScript code, potentially compromising user data, escalating privileges, or executing unauthorized actions. The issue exists in multiple areas, including content editing, link management, and file uploads.

Impact

The primary impact of CVE-2025-22388 is the compromise of confidentiality through the execution of arbitrary JavaScript in users' browsers. This can lead to theft of sensitive information such as authentication tokens, personal data, or other confidential content managed within the CMS. Attackers may also perform actions on behalf of users, potentially escalating privileges or accessing restricted areas indirectly. While integrity and availability are not directly affected, the breach of confidentiality can undermine trust and lead to further attacks such as phishing or session hijacking. Organizations with public-facing websites using the vulnerable CMS are at risk of reputational damage and regulatory penalties if user data is compromised. The requirement for some privileges and user interaction limits the ease of exploitation but does not eliminate the threat, especially in environments with many authenticated users or contributors.

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

support.optimizely.com/hc/en-us/articles/33182047260557-Content-Management-System-CMS-Security-Advisory-CMS-2025-01 (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 25 Feb 2026, 22:12 UTC

WeaknessesCWE-79

Technical details

References

Community reviews

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