Cross-Site Scripting (XSS) in mautic/core (CVE-2021-27910)
Summary
Cross-site scripting in mautic/core (CVE-2021-27910). Risk of unauthorized operations or information disclosure. Exploitable via POST /mailer/. Mitigation: upgrade to 4.0.0 or later.
Original description
The description as published by the source.
Insufficient sanitization / filtering allows for arbitrary JavaScript Injection in Mautic using the bounce management callback function. The values submitted in the "error" and "error_related_to" parameters of the POST request of the bounce management callback will be permanently stored and executed once the details page of an affected lead is opened by a Mautic user. An attacker with access to the bounce management callback function (identified with the Mailjet webhook, but it is assumed this will work uniformly across all kinds of webhooks) can inject arbitrary JavaScript Code into the "error" and "error_related_to" parameters of the POST request (POST /mailer//callback). It is noted that there is no authentication needed to access this function. The JavaScript Code is stored permanently in the web application and executed every time an authenticated user views the details page of a single contact / lead in Mautic. This means, arbitrary code can be executed to, e.g., steal or tamper with information.
Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV
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-2021-27910 has been found in mautic/core.
Attackers can target a specific entry point like POST /mailer/ over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade mautic/core to 4.0.0 or later.
If unsure, ask your IT team or search "mautic/core CVE-2021-27910" on the vendor's site.
CVE-2021-27910 (mautic/core) — CWE-79
Attack vector: remote (network-reachable) / unauthenticated
Attack surface: POST /mailer/
Patched: 4.0.0 — 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 mautic/core. Attackers reach the vulnerable code path via POST /mailer/ without authentication.
Check the vendor advisory for the affected versions of mautic/core. Attack surface: POST /mailer/.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 4.0.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual POST /mailer/ requests with malformed payloads or SQL meta-characters. 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
-
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。 -
2Hunt for indicators of compromise detect
grep 'POST /mailer/' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
POST /mailer/への異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。 -
3Apply patch patch
Upgrade mautic/core to 4.0.0ステージング環境で 4.0.0 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 2 で見つけた異常検知の続報チェックを含めること。
-
4Post-deployment verification verify
Replay attack against POST /mailer/ on staging to confirm patch closes the vector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 2 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
References
- advisory nvd.nist.gov
- package github.com
- patch github.com
- web github.com
- web github.com