CVE-2026-31640

/* * PoC Concept for CVE-2026-31640 * Triggering the rxrpc logic error requires interacting with a target * that uses the rxrpc protocol (e.g., AFS or kafs). * * This is a simulation of the network interaction. */ #include <stdio.h> #include <stdlib.h> #include <string.h> int main() { printf("[+] CVE-2026-31640 PoC Simulation\n"); printf("[+] Target: Linux Kernel with vulnerable rxrpc module\n"); printf("[+] Action: Sending crafted rxrpc response packets...\n"); // In a real exploit, an attacker would send specific rxrpc packets // with manipulated challenge serial numbers to trigger the // wrong skb comparison in rxrpc_post_response(). // // Pseudocode for packet injection: // 1. Establish rxrpc connection. // 2. Send initial challenge. // 3. Send response with serial number that should trigger update logic. // 4. Observe kernel panic or instability. printf("[!] Exploit logic depends on specific kernel configuration.\n"); return 0; }

{"cve": {"id": "CVE-2026-31640", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-04-24T15:16:43.357", "lastModified": "2026-04-27T20:20:22.350", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrxrpc: Fix use of wrong skb when comparing queued RESP challenge serial\n\nIn rxrpc_post_response(), the code should be comparing the challenge serial\nnumber from the cached response before deciding to switch to a newer\nresponse, but looks at the newer packet private data instead, rendering the\ncomparison always false.\n\nFix this by switching to look at the older packet.\n\nFix further[1] to substitute the new packet in place of the old one if\nnewer and also to release whichever we don't use."}], "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": "CWE-401"}]}], "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/20386e7f8d97475b8d815873e246423317ec4260", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/9132b1a7bf83b4a8042fffbc99d075b727a16742", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/b33f5741bb187db8ff32e8f5b96def77cc94dfca", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}