CVE-2025-57520 — decap-cms
MEDIUMCVE-2025-57520 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in decap-cms. No vendor fix is recorded yet; mitigation options are listed below.
Decap CMS Cross Site Scripting (XSS) vulnerability
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-57520.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2025-57520 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,567 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
decap-cmsnpmDescription
Decap CMS through 3.8.3 is vulnerable to stored Cross-Site Scripting (XSS) in the admin preview pane. User-controlled fields (e.g., title, description, tags, and body) are rendered in the preview without sufficient sanitization/escaping. An attacker with low-privilege author/contributor access can persist a JavaScript payload in content; when a maintainer or reviewer opens the preview, the payload executes in the CMS admin origin, enabling token/session theft or the execution of privileged actions via the DOM. The issue affects multiple input vectors and requires only passive interaction from the previewing user. As no patched version is available, administrators should restrict untrusted contributor roles and filter or disable preview rendering of untrusted HTML.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | decap-cms | all versions | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for decap-cms, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of decap-cms has shipped for CVE-2025-57520 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-57520 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-57520. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2025-57520 in your dependencies?
O3 Security finds CVE-2025-57520 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.