CVE-2026-3184

# The following is a conceptual PoC demonstration. # An attacker would typically use a network service (like telnet) that invokes login -h. import socket import sys # Target configuration TARGET_HOST = "target_server" TARGET_PORT = 23 # Telnet port, assuming it invokes login # Crafted hostname designed to bypass canonicalization checks # Example: Exploiting truncation or suffix stripping logic MALICIOUS_HOSTNAME = b"trusted_host.evil.com\n" def send_exploit(): print(f"[*] Attempting to connect to {TARGET_HOST}:{TARGET_PORT}") # In a real scenario, this interacts with the protocol that eventually calls 'login -h' # For example, sending a specific NAWS or NEW-ENVIRON variable in telnet # or raw bytes in rlogin protocol. # This represents the payload injection point payload = MALICIOUS_HOSTNAME print(f"[*] Sending crafted hostname: {payload}") print("[*] If successful, PAM_RHOST will be modified, bypassing access control.") # Actual socket interaction code would go here if __name__ == "__main__": send_exploit()

{"cve": {"id": "CVE-2026-3184", "sourceIdentifier": "[email protected]", "published": "2026-04-03T19:17:23.377", "lastModified": "2026-05-01T19:29:51.020", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "A flaw was found in util-linux. Improper hostname canonicalization in the `login(1)` utility, when invoked with the `-h` option, can modify the supplied remote hostname before setting `PAM_RHOST`. A remote attacker could exploit this by providing a specially crafted hostname, potentially bypassing host-based Pluggable Authentication Modules (PAM) access control rules that rely on fully qualified domain names. This could lead to unauthorized access."}], "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:N/I:L/A:N", "baseScore": 3.7, "baseSeverity": "LOW", "attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.2, "impactScore": 1.4}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N", "baseScore": 5.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.9, "impactScore": 1.4}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-289"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:kernel:util-linux:-:*:*:*:*:*:*:*", "matchCriteriaId": "92D87E07-AAB6-4D35-9577-B6E768FEAEAB"}, {"vulnerable": true, "criteria": "cpe:2.3:a:redhat:hardened_images:-:*:*:*:*:*:*:*", "matchCriteriaId": "87DEB507-5B64-47D7-9A50-3B87FD1E571F"}]}]}], "references": [{"url": "https://access.redhat.com/errata/RHSA-2026:7180", "source": "[email protected]", "tags": ["Third Party Advisory"]}, {"url": "https://access.redhat.com/security/cve/CVE-2026-3184", "source": "[email protected]", "tags": ["Third Party Advisory"]}, {"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2442570", "source": "[email protected]", "tags": ["Issue Tracking", "Third Party Advisory"]}]}}