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Vulnerabilities

Vulnerability · CVE-2026-40487

Postiz is an AI social media scheduling tool.

Published Apr 18, 2026 · catalog updated Jun 17, 2026 · Postiz is an AI

Check if you run it

No confirmed exploitation is on record for CVE-2026-40487. EPSS is 0.26%. Act only if a listed version of Postiz is an AI is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Postiz is an AI).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Critical9.0
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.26%
Remediation
Advisory link
Affected products
cpe gitroom/postiz

Postiz is an AI social media scheduling tool. Prior to version 2.21.6, a file upload validation bypass allows any authenticated user to upload arbitrary HTML, SVG, or other executable file types to the server by spoofing the header. The uploaded files are then served by nginx with a Content-Type derived from their original extension ( , ), enabling Stored Cross-Site Scripting (XSS) in the context of the application's origin. This can lead to session riding, account takeover, and full compromise of other users' accounts. Version 2.21.6 contains a fix.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe gitroom/postizversion unspecified

How to fix CVE-2026-40487

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-40487. EPSS is 0.26%. Act only if a listed version of Postiz is an AI is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-345: Insufficient Verification of Data Authenticity; CWE-434: Unrestricted Upload of File with Dangerous Type; CWE-79: Cross-site Scripting (XSS). EPSS 0.26%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Nginx security

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Apr 18, 2026 · NIST NVD

    Detected

    Postiz is an AI social media scheduling tool. Prior to version 2.21.6, a file upload validation bypass allows any authenticated user to upload arbitrary HTML, SVG, or other executable file types to the server by spoofing the header. The uploaded files are then served by nginx with a Content-Type derived from their original extension ( , ), enabling Stored Cross-Site Scripting (XSS) in the context

  2. Jun 17, 2026 · NIST NVD

    Updated

    Postiz is an AI social media scheduling tool. Prior to version 2.21.6, a file upload validation bypass allows any authenticated user to upload arbitrary HTML, SVG, or other executable file types to the server by spoofing the header. The uploaded files are then served by nginx with a Content-Type derived from their original extension ( , ), enabling Stored Cross-Site Scripting (XSS) in the context

Sources

  • CVE.orgVulnerability recordCVE-2026-40487

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-40487

    30-day exploitation probability 0.3%

    first.org
  • NIST NVDVulnerability recordCVE-2026-40487

    Postiz is an AI social media scheduling tool. Prior to version 2.21.6, a file upload validation bypass allows any authenticated user to upload arbitrary HTML, SVG, or other executable file types to the server by spoofing the header. The uploaded files are then serv

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.