Vulnerability in mautic/core (CVE-2026-9558)
Summary
Vulnerability in mautic/core (CVE-2026-9558). Successful exploitation can lead to full system takeover. Mitigation: upgrade to 7.1.2 or later.
Original description
The description as published by the source.
A Server-Side Template Injection (SSTI) vulnerability exists in Mautic's theme engine. The platform renders uploaded Twig templates without a sandbox or strict function restrictions. Authenticated users with permissions to create or upload themes can abuse this to execute arbitrary code on the hosting server (Remote Code Execution) or access restricted system files and configuration settings.
Source: NIST National Vulnerability Database 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-2026-9558 has been found in mautic/core.
Successful exploitation can lead to full system takeover. CVSS score: 9.9/10.
What to do: upgrade mautic/core to 7.1.2 or later.
If unsure, ask your IT team or search "mautic/core CVE-2026-9558" on the vendor's site.
CVE-2026-9558 (mautic/core) — CWE-1336 / CVSS v3 9.9
Attack vector: remote (network-reachable) / no user interaction
Patched: 7.1.2 — apply immediately
Workaround: There are no official workarounds.
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-1336) exists in mautic/core.
Check the vendor advisory for the affected versions of mautic/core.
Severity: Critical (CVSS 9.9/10). Successful exploitation can lead to full system takeover.
Update to 7.1.2.
Workaround: There are no official workarounds.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'mautic/core' . 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 'mautic/core' . | 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
mautic/coreを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply temporary workaround mitigate
There are no official workarounds.パッチが適用されるまでの応急処置として、There are no official workarounds. を実施。回避策の副作用 (機能低下) を確認した上で。
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3Apply patch patch
Upgrade mautic/core to 7.1.2ステージング環境で 7.1.2 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。
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4Post-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 nvd.nist.gov
- advisory github.com
- package github.com
- web github.com
- web packagist.org