Cyber Resilience

CVE-2026-40168

SSRF in Gitroom Postiz ≤ 2.21.5

Public PoCSSRF
Published
10 April 2026
Modified
14 April 2026
Patch / advisory
CVSS Score v3.1 8.2
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:L
EPSS Score 0.0037 30th percentile
Risk Priority 61 floored blend · peak EPSS

Summary

CVE-2026-40168 is a high-severity SSRF (CWE-918) vulnerability in Gitroom Postiz. Its CVSS base score is 8.2 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 30th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

This vulnerability is AI-related — categorised as LLM Application Platforms; in the Supply Chain and Deployment risk domain.

The strongest mitigations our analysis identified map to AC-4 (Information Flow Enforcement) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2026-40168 is a Server-Side Request Forgery (SSRF) vulnerability, classified under CWE-918, affecting Postiz, an AI social media scheduling tool, in versions prior to 2.21.5. The issue exists in the /api/public/stream endpoint, where the application validates the initially supplied URL to block direct requests to private or internal hosts but does not re-validate the final destination following HTTP redirects. This flaw enables attackers to provide a public HTTPS URL that passes initial validation and subsequently redirects the server-side request to an internal resource. The vulnerability carries a CVSS v3.1 base score of 8.2 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:L), indicating high severity due to significant confidentiality risks.

Unauthenticated attackers can exploit this vulnerability remotely with low complexity and no user interaction required. By submitting a specially crafted request to the /api/public/stream endpoint containing a public HTTPS URL that redirects to an internal host, attackers can compel the Postiz server to fetch internal resources. Successful exploitation primarily yields high confidentiality impact by exposing sensitive internal data, with a lesser availability impact potentially from resource exhaustion.

Mitigation is available via an upgrade to Postiz version 2.21.5, which includes the fix implemented in commit 30e8b777098157362769226d1b46d83ad616cb06. Additional details on the patch and remediation steps are provided in the GitHub Security Advisory GHSA-34w8-5j2v-h6ww and the corresponding release notes.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

Postiz is an AI social media scheduling tool. Prior to 2.21.5, the /api/public/stream endpoint is vulnerable to SSRF. Although the application validates the initially supplied URL and blocks direct private/internal hosts, it does not re-validate the final destination after HTTP…

more

redirects. As a result, an attacker can supply a public HTTPS URL that passes validation and then redirects the server-side request to an internal resource.

CWE(s)

AI Security AnalysisAI

AI Category
LLM Application Platforms
Risk Domain
Supply Chain and Deployment
OWASP Top 10 for LLMs 2025
None mapped
Classification Reason
Matched keywords: ai

Related Threats

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-34577Same product: Gitroom Postiz
CVE-2026-34590Same product: Gitroom Postiz
CVE-2026-34576Same product: Gitroom Postiz
CVE-2026-40487Same product: Gitroom Postiz
CVE-2026-42556Same product: Gitroom Postiz
CVE-2026-42298Same product: Gitroom Postiz
CVE-2026-31829Shared CWE-918
CVE-2026-42346Shared CWE-918
CVE-2025-56520Shared CWE-918
CVE-2025-65958Shared CWE-918

Affected Assets

gitroom
postiz
≤ 2.21.5

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V1.3.6
  • V1.5.3
  • V5.3.2
  • V10.4.7

Mitigating Controls (NIST 800-53 r5) AI

Information flow enforcement can restrict which destinations the server is allowed to contact on behalf of users.

Input validation directly stops untrusted URLs from being accepted and fetched without destination checks.

Boundary protection limits the network reach of server-initiated requests even if SSRF occurs.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure development practices directly include input validation and destination allow-listing that prevent SSRF.

DE.CM-09 partial match
prevents

Runtime monitoring of web applications and services can detect anomalous outbound requests indicative of SSRF.

ID.RA-01 partial match
prevents

Vulnerability identification processes can discover and record SSRF flaws in web applications.

PR.IR-01 partial match
prevents

Network segmentation and egress controls can limit the damage from successful SSRF requests.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

prevents

Operational threat data describing SSRF campaigns can be used to tighten outbound-request allow-lists and detection rules before attackers exploit them.

References