CVE-2026-42346
Server-Side Request Forgery in Postiz AI Scheduler
Publication date: 2026-05-08
Last updated on: 2026-05-08
Assigner: GitHub, Inc.
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| postiz | postiz | From 2.16.6 (inc) to 2.21.7 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-918 | The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability exists in Postiz, an AI social media scheduling tool, in versions from 2.16.6 up to but not including 2.21.7. It is a Time-of-Check-Time-of-Use (TOCTOU) issue affecting the Server-Side Request Forgery (SSRF) protections introduced between versions 2.21.4 and 2.21.6.
The function isSafePublicHttpsUrl() attempts to validate the target IP address by resolving DNS before allowing a request. However, the actual fetch() call that makes the request resolves DNS independently. This discrepancy allows an attacker who controls a DNS server to exploit DNS rebinding, redirecting requests to internal network addresses that should be protected.
This vulnerability was fixed in version 2.21.7.
How can this vulnerability impact me? :
An attacker exploiting this vulnerability can redirect server-side requests to internal network addresses by manipulating DNS responses. This can lead to unauthorized access to internal resources that are normally protected from external access.
The impact includes potential exposure of sensitive internal services or data, as the attacker can bypass SSRF protections and make the server perform requests to internal systems.
According to the CVSS score (6.5), the vulnerability has a high impact on confidentiality, a low impact on integrity, and no impact on availability.
What immediate steps should I take to mitigate this vulnerability?
The vulnerability is patched in Postiz version 2.21.7. The immediate step to mitigate this vulnerability is to upgrade Postiz to version 2.21.7 or later.