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.
Original description
The description as published by the source.
Twig is a template language for PHP. Prior to 3.26.0, several filters in twig/markdown-extra and twig/cssinliner-extra are registered with is_safe => [all], causing Twig to treat plain text or HTML output as safe in HTML, JavaScript, CSS, URL, and other contexts where the output is not properly escaped. This issue is fixed in version 3.26.0.
Source: GitHub Security Advisories (Global) 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-2026-46637 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: 5.4/10.
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 / CVSS v3 5.4
Attack vector: remote (network-reachable)
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.
A vulnerability (CWE-116) exists in twig/markdown-extra. Attackers reach the vulnerable code path via html.
Check the vendor advisory for the affected versions of twig/markdown-extra. Attack surface: html / css / url / html_to_markdown.
Severity: Medium (CVSS 5.4/10). Risk of unauthorized operations or information disclosure.
Update to 3.26.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
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
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。 -
2Apply 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を含めること。
-
3Post-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。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-46637 php-twig
- Ubuntu UBUNTU-CVE-2026-46637 php-twig
References
- advisory github.com
- advisory github.com
- advisory nvd.nist.gov
- package github.com
- patch github.com
- patch github.com
- web github.com
- web github.com
- web symfony.com
- web github.com
- web github.com