CVE-2026-30587 is a medium-severity (CVSS 5.4) Cross-site Scripting (XSS) vulnerability in @seafile/sdoc-editor. A fix is available for @seafile/sdoc-editor — see the affected versions and patch details below.
Seafile Server has multiple stored XSS vulnerabilities
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-30587.
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-2026-30587 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 378,156 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.
@seafile/sdoc-editornpmDescription
Multiple Stored XSS vulnerabilities exist in Seafile Server version 13.0.15,13.0.16-pro,12.0.14 and prior and fixed in 13.0.17, 13.0.17-pro, and 12.0.20-pro, via the Seadoc (sdoc) editor. The application fails to properly sanitize WebSocket messages regarding document structure updates. This allows authenticated remote attackers to inject malicious JavaScript payloads via the src attribute of embedded Excalidraw whiteboards or the href attribute of anchor tags
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @seafile/sdoc-editor | ≥ 3.0.0&&< 3.0.75 | 3.0.75npm install @seafile/sdoc-editor@3.0.75 |
| 📦npm | @seafile/sdoc-editor | all versions | 2.0.209npm install @seafile/sdoc-editor@2.0.209 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @seafile/sdoc-editor, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @seafile/sdoc-editor to 3.0.75 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-30587 is resolved across your whole dependency graph.
Workarounds
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-2026-30587 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-30587. 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-2026-30587 in your dependencies?
O3 Security finds CVE-2026-30587 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.