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

[ Why it matters ]Priority signals

• Public proof-of-concept exploit exists (CISA SSVC)

[ Description ]Official 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.

[ Fixes ]Fixes and patches

• quasar 2.23.3Fixed version · GitHub Advisories · npm package quasar: upgrade to 2.23.3 or later (affected <= 2.23.2)

[ Packages ]Affected open-source packages

• quasar npmAffected <= 2.23.2 · fixed in 2.23.3 · GHSA-68jq-fhch-4xq4

[ References ]References

• github.com/quasarframework/quasar/commit/7a954ddafa756afe95c8f633f48ed68a07209d3d
• github.com/quasarframework/quasar/releases/tag/quasar-v2.23.3
• github.com/quasarframework/quasar/security/advisories/GHSA-68jq-fhch-4xq4