CVE-2026-42346
Postiz: TOCTOU DNS rebinding bypasses all SSRF URL validation paths
CVSS Score
6.5
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-918 |
| Vendor | gitroomhq |
| Product | postiz-app |
| Published | May 8, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
Low
Availability
None
Affected Versions
gitroomhq / postiz-app
>= 2.16.6, < 2.21.7