Vulnerability in quasar (CVE-2026-106104)
Summary
Vulnerability in quasar (CVE-2026-106104). Risk of unauthorized operations or information disclosure. Exploitable via GET /404path. Mitigation: upgrade to 2.23.3 or later.
Original description
The description as published by the source.
Summary
One unauthenticated request with a crafted User-Agent stalls a Quasar SSR server for seconds.
Quasar auto-installs its Platform plugin on every server-side render, and Platform.parseSSR() feeds the raw, unbounded User-Agent request header into a chain of backtracking regular expressions in getMatch(). One of those patterns contains a greedy capture followed by two unbounded .* scans, so a crafted header costs time proportional to the cube of its length. An 8 KB User-Agent blocks the Node.js event loop for about 4.4 seconds, and a 16 KB one for about 35 seconds. During that time the server answers nobody, so a handful of tiny requests take an SSR site completely offline.
Details
Platform is in the autoInstalledPlugins array in ui/src/install-quasar.js, so it is installed unconditionally by app.use(Quasar, ...). The generated SSR entry (app-vite/templates/entry/app.js, called from app-vite/templates/entry/server-entry.js) runs that for every HTTP request, and it runs before routing, so requests to paths that do not exist are affected too. On the server the plugin takes the header verbatim (ui/src/plugins/platform/Platform.js):
Platform.parseSSR = ssrContext => {
const ua =
ssrContext.req.headers['user-agent'] ||
ssrContext.req.headers['User-Agent'] ||
''
return { ...client, userAgent: ua, is: getPlatform(ua) }
}
getPlatform() lowercases the string and passes it to getMatch() (`ui/src/plugins/platfo…
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-106104 has been found in quasar.
Attackers can target a specific entry point like GET /404path over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade quasar to 2.23.3 or later.
If unsure, ask your IT team or search "quasar CVE-2026-106104" on the vendor's site.
CVE-2026-106104 (quasar) — CWE-1333
Attack surface: GET /404path / Platform / autoInstalledPlugins / version
Patched: 2.23.3 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-1333) exists in quasar. Attackers reach the vulnerable code path via GET /404path.
Check the vendor advisory for the affected versions of quasar. Attack surface: GET /404path / Platform / autoInstalledPlugins / version.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 2.23.3.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual GET /404path requests with malformed payloads or SQL meta-characters. Run grep -r 'quasar' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'quasar' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
quasarを grep し、稼働しているサービス・バージョンを把握する。 -
2Hunt for indicators of compromise detect
grep 'GET /404path' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
GET /404pathへの異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。 -
3Apply patch patch
Upgrade quasar to 2.23.3ステージング環境で 2.23.3 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスと、Step 2 で見つけた異常検知の続報チェックを含めること。
-
4Post-deployment verification verify
Replay attack against GET /404path on staging to confirm patch closes the vectorパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番では Step 2 と同じログクエリでアラート再発が無いか継続監視。
Affected packages
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web github.com
- web github.com