Medium severity · published May 8, 2026
CVE-2026-42346
Postiz: TOCTOU DNS rebinding bypasses all SSRF URL validation paths
6.5
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
High
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 13% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
PO
postiz-app · gitroomhq
>= 2.16.6, < 2.21.7 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-42346
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-42346
github.com
https://github.com/gitroomhq/postiz-app/commit/071143dcb01cdeb9d5d7019892f4c6ff7b19dbeb
github.com
https://github.com/gitroomhq/postiz-app/releases/tag/v2.21.7
github.com
https://github.com/gitroomhq/postiz-app/security/advisories/GHSA-f7jj-p389-4w45
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