Cross-Site Scripting (XSS) in symfony/ux-icons (CVE-2026-55877)
Summary
Cross-site scripting in symfony/ux-icons (CVE-2026-55877). Risk of unauthorized operations or information disclosure. Exploitable via body. Mitigation: upgrade to 3.2.0 or later.
Original description
The description as published by the source.
Symfony UX is a JavaScript ecosystem for Symfony. From 2.17.0 before 2.36.1 and from 3.0.0 before 3.2.0, the ux_icon() Twig function is marked is_safe=['html'] and Icon::toHtml() inlines SVG source verbatim, allowing unsanitized local SVG files or Iconify on-demand JSON body responses containing nested script elements, on* event handlers, or dangerous URL schemes to execute cross-site scripting. This issue is fixed in versions 2.36.1 and 3.2.0.
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-2026-55877 has been found in symfony/ux-icons.
Attackers can target a specific entry point like body over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 6.1/10.
What to do: upgrade symfony/ux-icons to 3.2.0 or later.
If unsure, ask your IT team or search "symfony/ux-icons CVE-2026-55877" on the vendor's site.
CVE-2026-55877 (symfony/ux-icons) — CWE-79 / CVSS v3 6.1
Attack vector: remote (network-reachable) / unauthenticated
Attack surface: body / Icon / iconify.endpoint / IconFactory
Patched: 3.2.0 — 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.
Cross-site scripting (XSS) (CWE-79) exists in symfony/ux-icons. Attackers reach the vulnerable code path via body without authentication.
Check the vendor advisory for the affected versions of symfony/ux-icons. Attack surface: body / Icon / iconify.endpoint / IconFactory.
Severity: Medium (CVSS 6.1/10). Risk of unauthorized operations or information disclosure.
Update to 3.2.0.
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 'symfony/ux-icons' . 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/ux-icons' . | 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/ux-icons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/ux-icons to 3.2.0ステージング環境で 3.2.0 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
References
- advisory github.com
- advisory github.com
- advisory nvd.nist.gov
- package github.com
- patch github.com
- web github.com
- web github.com
- web github.com
- web github.com