CVE-2026-42346
Postiz: TOCTOU DNS rebinding bypasses all SSRF URL validation paths
- State
- Published
- Severity
- 6.5 Medium
- Published
- May 8, 2026
- Updated
- May 11, 2026
- Reserved
- Apr 26, 2026
Description
Postiz is an AI social media scheduling tool. From version 2.16.6 to before version 2.21.7, all SSRF protections added in v2.21.4–v2.21.6 share a fundamental TOCTOU (Time-of-Check-Time-of-Use) vulnerability: isSafePublicHttpsUrl() resolves DNS to validate the target IP, but subsequent fetch() calls resolve DNS independently. An attacker controlling a DNS server can exploit this gap via DNS rebinding to redirect requests to internal network addresses. This issue has been patched in version 2.21.7.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 6.5 Medium | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N | GitHub_M |
Weaknesses
- CWE-918 Server-Side Request Forgery (SSRF)
Affected Products
| Product | Versions |
|---|---|
postiz-appgitroomhq |
|
References
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