CVE-2025-57520VulnerabilityPublished 10 Sep 2025Updated 11 Sep 2025

CVE-2025-57520: n/a

Source CVE Database V5

Not known to be exploited · CVSS 6.1 Medium.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

6.1Medium

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 26% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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 10 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

AI-suggested

To mitigate CVE-2025-57520, European organizations should prioritize the following actions: 1) Apply patches or updates from Decap CMS as soon as they become available to address the input sanitization flaws. 2) In the absence of official patches, implement web application firewall (WAF) rules to detect and block suspicious script injection attempts targeting the vulnerable input fields (body, tags, title, description). 3) Restrict access to the CMS preview pane to trusted users only, minimizing exposure to untrusted or anonymous users. 4) Conduct thorough input validation and output encoding on all user-supplied content rendered in the preview pane, ideally using context-aware encoding libraries to neutralize script injection vectors. 5) Educate content editors and administrators about the risks of viewing untrusted content previews and encourage cautious behavior when handling content from unknown sources. 6) Monitor CMS logs and network traffic for unusual activity indicative of exploitation attempts. 7) Consider implementing Content Security Policy (CSP) headers to restrict the execution of inline scripts and reduce the impact of potential XSS payloads. These measures, combined, will reduce the attack surface and mitigate the risk until a full patch is deployed.

Description

A Cross Site Scripting (XSS) vulnerability exists in Decap CMS thru 3.8.3. Input fields such as body, tags, title, and description are not properly sanitized before being rendered in the content preview pane. This enables an attacker to inject arbitrary JavaScript which executes whenever a user views the preview panel. The vulnerability affects multiple input vectors and does not require user interaction beyond viewing the affected content.

Impact

For European organizations using Decap CMS, this vulnerability poses a risk of client-side code injection leading to session hijacking, unauthorized actions, or data leakage within the CMS environment. Since the vulnerability executes in the context of the CMS preview pane, attackers could target content editors or administrators, potentially compromising sensitive content management workflows. This could lead to unauthorized content modifications, leakage of internal information, or pivoting to further attacks within the organization’s network. The medium severity score reflects that while the vulnerability does not directly impact system availability, it compromises confidentiality and integrity, which are critical for maintaining trust and operational security. European organizations in sectors such as media, publishing, education, and government that rely on Decap CMS for content management are particularly at risk. Additionally, the vulnerability could be leveraged in targeted phishing or social engineering campaigns to trick users into viewing malicious content previews, amplifying the risk. The lack of required privileges lowers the barrier for attackers, increasing the likelihood of exploitation if the vulnerability is not remediated promptly.

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 18 Sep 2025, 00:41 UTC

WeaknessesCWE-79

Technical details

References

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