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CVE-2026-46637
Vulnerability in twig/markdown-extra (CVE-2026-46637)
Summary
vulnerability in twig/markdown-extra (CVE-2026-46637). Risk of unauthorized operations or information disclosure. Exploitable via ``html``. Mitigation: upgrade to `3.26.0` or later.
AI summary snake-internal / snake-material-v2
A vulnerability tracked as **CVE-2026-46637** has been found in twig/markdown-extra.
Attackers can target a specific entry point like ``html`` over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: ?/10.
What to do: upgrade twig/markdown-extra to **3.26.0** or later.
If unsure, ask your IT team or search "twig/markdown-extra CVE-2026-46637" on the vendor's site.
CVE-2026-46637 (twig/markdown-extra) — CWE-116 /
Attack surface: `html` / `css` / `url` / `html_to_markdown`
Patched: `3.26.0` — 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
**A vulnerability** (CWE-116) exists in twig/markdown-extra. Attackers reach the vulnerable code path via ``html`` without authentication.
📍 Affected scope
twig/markdown-extra — . Attack surface: `html` / `css` / `url` / `html_to_markdown`.
🔥 Severity
Severity: ?. Risk of unauthorized operations or information disclosure
🔧 How to fix
Update to **3.26.0**.
🛡️ 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 'twig/markdown-extra' .` 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 'twig/markdown-extra' . | 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 `twig/markdown-extra` 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 twig/markdown-extra to 3.26.0ステージング環境で 3.26.0 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
twig/markdown-extra
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.26.0"}]}]
composer
twig/cssinliner-extra
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.26.0"}]}]
Packagist
twig/markdown-extra
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.26.0"}]}]
Packagist
twig/cssinliner-extra
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.26.0"}]}]
References
- package https://github.com/twigphp/Twig
- web [email protected]
- web https://github.com/FriendsOfPHP/security-advisories/blob/master/twig/cssinliner-extra/CVE-2026-46637.yaml
- web https://github.com/FriendsOfPHP/security-advisories/blob/master/twig/markdown-extra/CVE-2026-46637.yaml
- web https://symfony.com/cve-2026-46637
- web https://github.com/advisories/GHSA-jv8m-2544-3pg3
- web [email protected]
- web [email protected]
- web [email protected]