GHSA-m6fv-jmcg-4jfg
MEDIUMGHSA-m6fv-jmcg-4jfg is a medium-severity (CVSS 5) Cross-site Scripting (XSS) vulnerability in send. O3 Security confirms whether GHSA-m6fv-jmcg-4jfg is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
send vulnerable to template injection that can lead to XSS
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
sendnpmDescription
Impact
passing untrusted user input - even after sanitizing it - to SendStream.redirect() may execute untrusted code
Patches
this issue is patched in send 0.19.0
Workarounds
users are encouraged to upgrade to the patched version of express, but otherwise can workaround this issue by making sure any untrusted inputs are safe, ideally by validating them against an explicit allowlist
Details
successful exploitation of this vector requires the following:
- The attacker MUST control the input to response.redirect()
- express MUST NOT redirect before the template appears
- the browser MUST NOT complete redirection before:
- the user MUST click on the link in the template
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | send | all versions | 0.19.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for send. 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 send to 0.19.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-m6fv-jmcg-4jfg 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 GHSA-m6fv-jmcg-4jfg 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 GHSA-m6fv-jmcg-4jfg. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-m6fv-jmcg-4jfg in your dependencies?
O3 detects GHSA-m6fv-jmcg-4jfg across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.