Vulnerability in symfony/html-sanitizer (CVE-2026-45064)
Summary
Vulnerability in symfony/html-sanitizer (CVE-2026-45064). Risk of unauthorized operations or information disclosure. Exploitable via HtmlSanitizer. Mitigation: upgrade to 8.0.12 or later.
Original description
The description as published by the source.
Symfony is a PHP framework for web and console applications and a set of reusable PHP components. From 6.1.0-BETA1 until 6.4.40, 7.4.12, and 8.0.12, UrlSanitizer::parse() passes Unicode explicit-direction BiDi formatting characters through into sanitized href and src attributes, allowing sanitized content to display a link destination that visually differs from the actual destination and enabling phishing-style visual spoofing. This issue is fixed in versions 6.4.40, 7.4.12, and 8.0.12.
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-2026-45064 has been found in symfony/html-sanitizer.
Attackers can target a specific entry point like HtmlSanitizer over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 6.1/10.
What to do: upgrade symfony/html-sanitizer to 8.0.12 or later.
If unsure, ask your IT team or search "symfony/html-sanitizer CVE-2026-45064" on the vendor's site.
CVE-2026-45064 (symfony/html-sanitizer) — CWE-451 / CVSS v3 6.1
Attack vector: remote (network-reachable) / unauthenticated
Attack surface: HtmlSanitizer / href / src
Patched: 8.0.12 — 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-451) exists in symfony/html-sanitizer. Attackers reach the vulnerable code path via HtmlSanitizer without authentication.
Check the vendor advisory for the affected versions of symfony/html-sanitizer. Attack surface: HtmlSanitizer / href / src.
Severity: Medium (CVSS 6.1/10). Risk of unauthorized operations or information disclosure.
Update to 8.0.12.
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 'symfony/html-sanitizer' . 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
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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。 -
2Apply patch patch
Upgrade symfony/html-sanitizer to 8.0.12ステージング環境で 8.0.12 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-2026-45064 symfony Fixed in: 6.4.41+dfsg-0+deb13u1
- Ubuntu UBUNTU-CVE-2026-45064 symfony
References
- advisory github.com
- advisory github.com
- advisory nvd.nist.gov
- package github.com
- patch github.com
- web github.com
- web github.com
- web symfony.com
- web github.com
- web github.com
- web github.com
- web github.com