CVE-2025-59837
HIGHCVE-2025-59837 is a high-severity (CVSS 7.2) Cross-site Scripting (XSS) vulnerability in astro. O3 Security confirms whether CVE-2025-59837 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
astro allows bypass of image proxy domain validation leading to SSRF and potential XSS
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
astronpmDescription
Astro is a web framework that includes an image proxy. In versions 5.13.4 and later before 5.13.10, the image proxy domain validation can be bypassed by using backslashes in the href parameter, allowing server-side requests to arbitrary URLs. This can lead to server-side request forgery (SSRF) and potentially cross-site scripting (XSS). This vulnerability exists due to an incomplete fix for CVE-2025-58179. Fixed in 5.13.10.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | astro | ≥ 5.13.4&&< 5.13.10 | 5.13.10 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for astro. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update astro to 5.13.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-59837 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 pinpoints whether CVE-2025-59837 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2025-59837. 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-2025-59837 in your dependencies?
O3 detects CVE-2025-59837 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.