CVE-2026-42346 — Postiz: TOCTOU DNS rebinding bypasses all SSRF URL validation paths
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-Che…
Published: 2026-05-08 · CVSS: 6.5 · CVSS 3.1
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7