CVE-2026-40255
MEDIUMCVE-2026-40255 is a medium-severity (CVSS 6.1) vulnerability in @adonisjs/http-server. O3 Security confirms whether CVE-2026-40255 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
@adonisjs/http-server has an Open Redirect vulnerability
Blast Radius
@adonisjs/http-server📦@adonisjs/core📦@adonisjs/http-serverReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.
Description
AdonisJS HTTP Server is a package for handling HTTP requests in the AdonisJS framework. In @adonisjs/http-server versions prior to 7.8.1 and 8.0.0-next.0 through 8.1.3, and @adonisjs/core versions prior to 7.4.0, the response.redirect().back() method reads the Referer header from the incoming HTTP request and redirects to that URL without validating the host.An attacker who can influence the Referer header can cause the application to redirect users to a malicious external site. This affects all AdonisJS applications that use response.redirect().back() or response.redirect('back'). This issue has been fixed in versions 7.8.1 and 8.2.0 and 7.4.0 of @adonisjs/core.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @adonisjs/http-server | ≥ 8.0.0-next.0&&< 8.2.0 | 8.2.0 |
| 📦npm | @adonisjs/core | all versions | 7.3.1 |
| 📦npm | @adonisjs/http-server | all versions | 7.8.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @adonisjs/http-server. 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 @adonisjs/http-server to 8.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-40255 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-2026-40255 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-2026-40255. 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-2026-40255 in your dependencies?
O3 detects CVE-2026-40255 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.