CVE-2026-43098

/* * Conceptual PoC for CVE-2026-43098 * This demonstrates the logic flow causing the NULL pointer dereference. * Requires hardware (Samsung S3FWRN5) to trigger in reality. */ #include <linux/module.h> #include <net/sock.h> // Simulating the vulnerable logic flow void vulnerable_logic_simulation() { struct sk_buff *recv_skb = NULL; int count; // Step 1: Consume bytes into current skb (Assume skb existed) // ... processing logic ... // Step 2: Current frame is delivered, skb is consumed. // recv_skb is now conceptually NULL or stale. // Step 3: Attempt to allocate new skb recv_skb = alloc_skb(1024, GFP_KERNEL); if (!recv_skb) { // VULNERABILITY: Allocation failed, but bytes were already consumed. // The function returns 0, but accounting is broken. return; // recv_skb remains NULL } // Step 4: Next interrupt calls this // skb_put_u8(recv_skb, data); // NULL Pointer Dereference here! } // Fix logic: Allocate before consuming void fixed_logic_simulation() { struct sk_buff *recv_skb = NULL; // Allocate BEFORE consuming bytes if (!recv_skb) { recv_skb = alloc_skb(1024, GFP_KERNEL); if (!recv_skb) { return -ENOMEM; // Return error, don't consume bytes } } // Safe to consume now // skb_put_u8(recv_skb, data); }

{"cve": {"id": "CVE-2026-43098", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-06T10:16:23.250", "lastModified": "2026-05-14T19:24:03.903", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfc: s3fwrn5: allocate rx skb before consuming bytes\n\ns3fwrn82_uart_read() reports the number of accepted bytes to the serdev\ncore. The current code consumes bytes into recv_skb and may already\ndeliver a complete frame before allocating a fresh receive buffer.\n\nIf that alloc_skb() fails, the callback returns 0 even though it has\nalready consumed bytes, and it leaves recv_skb as NULL for the next\nreceive callback. That breaks the receive_buf() accounting contract and\ncan also lead to a NULL dereference on the next skb_put_u8().\n\nAllocate the receive skb lazily before consuming the next byte instead.\nIf allocation fails, return the number of bytes already accepted."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "baseScore": 5.5, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "NVD-CWE-Other"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.11", "versionEndExcluding": "6.6.136", "matchCriteriaId": "40B9BA4F-676E-4F69-BF6A-3BF9DAF97D80"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "6.12.83", "matchCriteriaId": "7F0AE5B5-23AC-4DCC-B37A-51CA1DAE7BA8"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13", "versionEndExcluding": "6.18.24", "matchCriteriaId": "8126B8B8-6D0B-4443-86C1-672AEE893555"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "6.19.14", "matchCriteriaId": "D6A8A074-BBF4-4803-ABED-519A839435BB"}, {"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/09822d3d6f68a0cdc4626e0c507324a4927f55a9", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/5c14a19d5b1645cce1cb1252833d70b23635b632", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/6d931680a9851481c3243689488eafed08eeff71", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/7c31f7a599cf00fad3c204092a91a924126c67e4", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/d8c2aa3c4a1ec530a485e46a1c4f1a118bb00156", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}