HOMEVULNERABILITIESCVE-2026-42556
HIGH

CVE-2026-42556

CWE-79Published: May 8, 2026· Updated: May 13, 2026

8.9
CVSS v3.1
EPSS:0.04%probability of exploitation in 30 daysPercentile:12.0th

Official Description

Postiz is an AI social media scheduling tool. From version 2.21.6 to before version 2.21.7, any authenticated user who can create a post can store arbitrary HTML in post content by tampering their own save request and send the public preview link /p/<postId>?share=true to another user. The preview page renders that stored HTML with dangerouslySetInnerHTML on the main application origin. This issue has been patched in version 2.21.7.

NVD Source

Technical Analysis

CVE-2026-42556 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), with a CVSS base score of 8.9.

The vulnerability has a "Changed" scope, meaning successful exploitation can impact components beyond the vulnerable component itself — such as the host operating system or adjacent services.

From a weakness classification perspective (CWE-79): Cross-site scripting (XSS) vulnerabilities allow attackers to inject malicious scripts into web pages viewed by other users.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.Low
User InteractionRequired
ScopeChanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityLow
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:L

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
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All References (2)

Quick Facts

CVE IDCVE-2026-42556
CVSS Score8.9 / 10
SeverityHIGH
WeaknessCWE-79
CISA KEVNo
EPSS (30d)0.04%
PublishedMay 8, 2026

Related CVEs (CWE-79)

Recommended Actions

  • Apply vendor patches immediately
  • Monitor CVE-2026-42556 in threat intel feeds
  • Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.