Unrestricted File Upload in ghost (CVE-2026-53948)
Summary
Vulnerability in ghost (CVE-2026-53948). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 6.21.1 or later.
Original description
The description as published by the source.
Ghost is a Node.js content management system. From 6.19.4 until 6.21.1, insufficient validation of the client-supplied Content-Type on Ghost's Admin API file upload endpoint allowed uploaded files to be served from the site with an attacker-chosen content type on S3/GCS storage backends. On installations that serve uploaded files from the same origin as the site, this could have been used to facilitate stored cross-site scripting against site visitors or staff. This vulnerability is fixed in 6.21.1.
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-2026-53948 has been found in ghost.
Risk of unauthorized operations or information disclosure. CVSS score: 5.4/10.
What to do: upgrade ghost to 6.21.1 or later.
If unsure, ask your IT team or search "ghost CVE-2026-53948" on the vendor's site.
CVE-2026-53948 (ghost) — CWE-434 / CVSS v3 5.4
Attack vector: remote (network-reachable)
Patched: 6.21.1 — 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-434) exists in ghost.
Check the vendor advisory for the affected versions of ghost.
Severity: Medium (CVSS 5.4/10). Risk of unauthorized operations or information disclosure.
Update to 6.21.1.
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 'ghost' . 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 'ghost' . | 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
ghost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 ghost to 6.21.1ステージング環境で 6.21.1 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 nvd.nist.gov
- advisory github.com
- package github.com
- web github.com
- web github.com
- web github.com
- web github.com