CVE-2026-34577

Postiz: Unauthenticated Full-Read SSRF via /public/stream Endpoint with Trivially Bypassable Extension Check

HIGH
8.6
CVSS Score
Published: April 2, 2026 at 05:24 PM UTC
Updated: July 24, 2026 at 09:20 PM UTC
2 products affected across 2 vendorsPostizPostiz

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Severity
HIGH8.6
Exploit prediction
EPSS 0.5%
SSVC
PoC

Description

Postiz is an AI social media scheduling tool. Prior to version 2.21.3, the GET /public/stream endpoint in PublicController accepts a user-supplied url query parameter and proxies the full HTTP response back to the caller. The only validation is url.endsWith('mp4'), which is trivially bypassable by appending .mp4 as a query parameter value or URL fragment. The endpoint requires no authentication and has no SSRF protections, allowing an unauthenticated attacker to read responses from internal services, cloud metadata endpoints, and other network-internal resources. This issue has been patched in version 2.21.3.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 2.21.3
Affected range stops below 2.21.3, so it looks safe — our inference, not a vendor statement
v < 2.21.3
Affected range stops below 2.21.3, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (2)

x_refsource_CONFIRMExploitMitigationVendor Advisory
Source: cverecord
https://github.com/gitroomhq/postiz-app/security/advisories/GHSA-mv6h-v3jg-g539
x_refsource_MISCProductRelease Notes
Source: cverecord
https://github.com/gitroomhq/postiz-app/releases/tag/v2.21.3

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.6HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-918

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