SSRF (Server-Side Request Forgery) in Postiz (CVE-2026-34576)
Summary
SSRF in Postiz (CVE-2026-34576). Confidential information can be exposed externally. Exploitable via POST /public/v1/upload-from-url.
Original description
The description as published by the source.
Postiz is an AI social media scheduling tool. Prior to version 2.21.3, the POST /public/v1/upload-from-url endpoint accepts a user-supplied URL and fetches it server-side using axios.get() with no SSRF protections. The only validation is a file extension check (.png, .jpg, etc.) which is trivially bypassed by appending an image extension to any URL path. An authenticated API user can fetch internal network resources, cloud instance metadata, and other internal services, with the response data uploaded to storage and returned to the attacker. This issue has been patched in version 2.21.3.
Source: NIST National Vulnerability Database NVD
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-34576 has been found in Postiz.
Attackers can target a specific entry point like POST /public/v1/upload-from-url over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 7.7/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Postiz CVE-2026-34576" on the vendor's site.
CVE-2026-34576 (Postiz) — CWE-918 / CVSS v3 7.7
Attack vector: remote (network-reachable) / no user interaction
Attack surface: POST /public/v1/upload-from-url
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
SSRF (CWE-918) exists in Postiz. Attackers reach the vulnerable code path via POST /public/v1/upload-from-url.
Check the vendor advisory for the affected versions of Postiz. Attack surface: POST /public/v1/upload-from-url.
Severity: High (CVSS 7.7/10). Confidential information can be exposed externally.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual POST /public/v1/upload-from-url requests with malformed payloads or SQL meta-characters. Run grep -r 'Postiz' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'Postiz' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
Postizを grep し、稼働しているサービス・バージョンを把握する。 -
2Hunt for indicators of compromise detect
grep 'POST /public/v1/upload-from-url' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
POST /public/v1/upload-from-urlへの異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。 -
3Post-deployment verification verify
Replay attack against POST /public/v1/upload-from-url on staging to confirm patch closes the vectorパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番では Step 2 と同じログクエリでアラート再発が無いか継続監視。