Vulnerability in craftcms/cms (CVE-2026-50279)
Summary
Vulnerability in craftcms/cms (CVE-2026-50279). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 5.9.21 or later.
Original description
The description as published by the source.
Craft CMS is a content management system (CMS). IN versions 5.0.0-RC1 and above prior to 5.9.21, theEntriesController::actionSaveEntry() performs entry-edit permission checks before request-controlled author changes are applied to the model, allowing for authorship spoofing. The subsequent author mutation path accepts attacker-supplied authors / author parameters and allows the change when the current user is one of the old authors. Because the controller does not re-run authorization after mutating the author list, a low-privileged user can reassign an entry’s authorship to another user without holding the dedicated peer-author-change permission. This issue has been fixed in version 5.9.21.
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-2026-50279 has been found in craftcms/cms.
Risk of unauthorized operations or information disclosure.
What to do: upgrade craftcms/cms to 5.9.21 or later.
If unsure, ask your IT team or search "craftcms/cms CVE-2026-50279" on the vendor's site.
CVE-2026-50279 (craftcms/cms) — CWE-285
Patched: 5.9.21 — 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-285) exists in craftcms/cms.
Check the vendor advisory for the affected versions of craftcms/cms.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 5.9.21.
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 'craftcms/cms' . 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 'craftcms/cms' . | 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
craftcms/cms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 craftcms/cms to 5.9.21ステージング環境で 5.9.21 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
- patch github.com
- web github.com