Quasar Framework: Super-linear regex backtracking on User-Agent lets one request stall a Quasar SSR server

Why it is Amber

• CVSS 8.7 high
• Remotely exploitable without logging in
• On your watchlist: npm

Affected packages

References

• https://github.com/advisories/GHSA-68jq-fhch-4xq4
• https://github.com/quasarframework/quasar/security/advisories/GHSA-68jq-fhch-4xq4
• https://nvd.nist.gov/vuln/detail/CVE-2026-106104
• https://github.com/quasarframework/quasar/commit/7a954ddafa756afe95c8f633f48ed68a07209d3d
• https://github.com/quasarframework/quasar/releases/tag/quasar-v2.23.3
• https://github.com/advisories/GHSA-68jq-fhch-4xq4

Original description

Quasar Framework is a framework for building high-performance Vue.js user interfaces. Prior to 2.23.3, Platform.parseSSR() passed an unbounded User-Agent request header to getMatch() in ui/src/plugins/platform/Platform.js, whose browser-detection expressions combined greedy captures with repeated unbounded scans. Platform belongs to autoInstalledPlugins, so this parsing occurs before routing for every SSR request. A crafted unauthenticated request containing repeated version tokens without a terminating Safari token causes super-linear backtracking and blocks the Node.js event loop, delaying every other SSR request. SPA, PWA, Electron, Cordova, Capacitor, browser-extension, and static-site-generation targets are not affected because they do not parse an attacker-controlled request header through this path. This issue is fixed in version 2.23.3.