Ralph SlootenのMailpitにおけるサーバサイドのリクエストフォージェリの脆弱性
Summary
Vulnerability reported (CVE-2026-23845). Risk of unauthorized operations or information disclosure. Exploitable via isValidURL.
Original description
The description as published by the source.
Mailpit is an email testing tool and API for developers. Versions prior to 1.28.3 are vulnerable to Server-Side Request Forgery (SSRF) via HTML Check CSS Download. The HTML Check feature (/api/v1/message/{ID}/html-check) is designed to analyze HTML emails for compatibility. During this process, the inlineRemoteCSS() function automatically downloads CSS files from external `` tags to inline them for testing. Version 1.28.3 fixes the issue.
Source: JVN (Japan Vulnerability Notes) 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-2026-23845 has been found.
Attackers can target a specific entry point like isValidURL over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "CVE-2026-23845" on the vendor's site.
CVE-2026-23845
Attack surface: isValidURL / net.Dialer.DialContext / Transport.DialContext / http.Client
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 (unclassified) has been reported. Attackers reach the vulnerable code path via isValidURL.
Check the vendor advisory for the affected versions. Attack surface: isValidURL / net.Dialer.DialContext / Transport.DialContext / http.Client.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
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. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで影響コンポーネントを特定する。
-
2Post-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。
References
- advisory github.com
- advisory github.com
- advisory nvd.nist.gov
- JVN JVNDB-2026-025876
- patch github.com
- web github.com