Cross-Site Scripting (XSS) in ghost (CVE-2021-29484)
Summary
Cross-site scripting in ghost (CVE-2021-29484). Confidential information can be exposed externally. Mitigation: upgrade to 4.3.3 or later.
Original description
The description as published by the source.
Ghost is a Node.js CMS. An unused endpoint added during the development of 4.0.0 has left sites vulnerable to untrusted users gaining access to Ghost Admin. Attackers can gain access by getting logged in users to click a link containing malicious code. Users do not need to enter credentials and may not know they've visited a malicious site. Ghost(Pro) has already been patched. We can find no evidence that the issue was exploited on Ghost(Pro) prior to the patch being added. Self-hosters are impacted if running Ghost a version between 4.0.0 and 4.3.2. Immediate action should be taken to secure your site. The issue has been fixed in 4.3.3, all 4.x sites should upgrade as soon as possible. As the endpoint is unused, the patch simply removes it. As a workaround blocking access to /ghost/preview can also mitigate the issue.
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-2021-29484 has been found in ghost.
Confidential information can be exposed externally.
What to do: upgrade ghost to 4.3.3 or later.
If unsure, ask your IT team or search "ghost CVE-2021-29484" on the vendor's site.
CVE-2021-29484 (ghost) — CWE-79
Attack vector: remote (network-reachable) / unauthenticated
Patched: 4.3.3 — 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 ghost.
Check the vendor advisory for the affected versions of ghost.
Severity: ?. Confidential information can be exposed externally.
Update to 4.3.3.
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 4.3.3ステージング環境で 4.3.3 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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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 blog.sonarsource.com
- advisory forum.ghost.org
- advisory npmjs.com
- package github.com
- web nvd.nist.gov
- web github.com
- web security.netapp.com