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CVE-2026-48761
Cross-Site Scripting (XSS) in symfony/html-sanitizer (CVE-2026-48761)
Summary
cross-site scripting in symfony/html-sanitizer (CVE-2026-48761). Risk of unauthorized operations or information disclosure. Exploitable via ``content``. Mitigation: upgrade to `8.0.13` or later.
AI summary snake-internal / snake-material-v2
A vulnerability tracked as **CVE-2026-48761** has been found in symfony/html-sanitizer.
Attackers can target a specific entry point like ``content`` over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: ?/10.
What to do: upgrade symfony/html-sanitizer to **8.0.13** or later.
If unsure, ask your IT team or search "symfony/html-sanitizer CVE-2026-48761" on the vendor's site.
CVE-2026-48761 (symfony/html-sanitizer) — CWE-79 /
Attack surface: `content` / `UrlAttributeSanitizer` / `data` / `codebase`
Patched: `8.0.13` — 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.
❓ What is the problem
**Cross-site scripting (XSS)** (CWE-79) exists in symfony/html-sanitizer. Attackers reach the vulnerable code path via ``content`` without authentication.
📍 Affected scope
symfony/html-sanitizer — . Attack surface: `content` / `UrlAttributeSanitizer` / `data` / `codebase`.
🔥 Severity
Severity: ?. Risk of unauthorized operations or information disclosure
🔧 How to fix
Update to **8.0.13**.
🛡️ Workaround
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
🔍 Detection
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run `grep -r 'symfony/html-sanitizer' .` against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response Actions (7 steps)
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'symfony/html-sanitizer' . | 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 `symfony/html-sanitizer` を grep し、稼働しているサービス・バージョンを把握する。
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6Apply patch patch
Upgrade symfony/html-sanitizer to 8.0.13ステージング環境で 8.0.13 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 3 で見つけた異常検知の続報チェックを含めること。
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7Post-deployment verification verify
Confirm patched version is live in production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 3 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
composer
symfony/html-sanitizer
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"8.0.13"}]}]
composer
symfony/symfony
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"8.0.13"}]}]
Packagist
symfony/html-sanitizer
[{"type":"ECOSYSTEM","events":[{"introduced":"8.0.0"},{"fixed":"8.0.13"}]}]
Packagist
symfony/symfony
[{"type":"ECOSYSTEM","events":[{"introduced":"8.0.0"},{"fixed":"8.0.13"}]}]
References
- package https://github.com/symfony/symfony
- web https://github.com/symfony/symfony/security/advisories/GHSA-x5qj-865h-mgvm
- web https://github.com/symfony/symfony/commit/069a70f9f26e61e9de3b7f9a864a86ed24b36bd0
- web https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/html-sanitizer/CVE-2026-48761.yaml
- web https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/symfony/CVE-2026-48761.yaml
- web https://symfony.com/cve-2026-48761
- web https://github.com/advisories/GHSA-x5qj-865h-mgvm