# CVE-2026-34577: Postiz: Unauthenticated Full-Read SSRF via /public/stream Endpoint with Trivially Bypassable Extension Check

> Unauthenticated attackers can read internal network resources via Server-Side Request Forgery in Postiz due to insufficient URL validation.

- **Severity:** High 8.6 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 2 Apr 2026
- **Updated:** 3 Apr 2026
- **Also known as:** GHSA-mv6h-v3jg-g539

## What is CVE-2026-34577?

CVE-2026-34577 is a high-severity server-side request forgery vulnerability in gitroomhq postiz-app, published on 2 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-918 (Server-Side Request Forgery)

## Which versions are affected by CVE-2026-34577?

It affects 1 product.


Products: Gitroom Postiz.

## How do I fix CVE-2026-34577?

No fix has been published for CVE-2026-34577 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-34577 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34577 exists.

## Other vulnerabilities in gitroomhq postiz-app

- [CVE-2026-42298](https://insights.sbomify.com/CVE-2026-42298/): Postiz: Arbitrary Code Execution and Token Exfiltration in pr-docker-build.yml via untrusted Dockerfile.dev (critical 10.0)
- [CVE-2026-42556](https://insights.sbomify.com/CVE-2026-42556/): Postiz stored XSS in public preview page (high 8.9)
- [CVE-2026-40487](https://insights.sbomify.com/CVE-2026-40487/): Postiz Has Unrestricted File Upload via MIME Type Spoofing that Leads to Stored XSS (high 8.9)
- [CVE-2026-34576](https://insights.sbomify.com/CVE-2026-34576/): Postiz: SSRF in upload-from-url endpoint allows fetching internal resources and cloud metadata (high 8.3)
- [CVE-2026-40168](https://insights.sbomify.com/CVE-2026-40168/): Postiz has Server-Side Request Forgery via Redirect Bypass in /api/public/stream (high 8.2)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-34577 and fix it if it is affected.

What it is: CVE-2026-34577 is a high-severity server-side request forgery vulnerability in gitroomhq postiz-app, published on 2 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34577 exists.

Affected product: gitroomhq postiz-app. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-34577/ (Markdown: https://insights.sbomify.com/CVE-2026-34577/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-34577
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-34577
- OSV: https://osv.dev/vulnerability/CVE-2026-34577

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-34577/
Summaries are generated and may contain mistakes; the official description above is the record.