CVE-2023-53566

// CVE-2023-53566 PoC - Trigger null pointer dereference in nft_set_rbtree // This PoC demonstrates triggering the null deref in nft_rbtree_gc_elem() // Requires: CAP_NET_ADMIN or root privileges to manipulate nftables #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/socket.h> #include <linux/netlink.h> #include <linux/netfilter.h> #include <linux/netfilter/nfnetlink.h> #include <linux/netfilter/nf_tables.h> #include <linux/netfilter/nf_tables_compat.h> // Note: This is a conceptual PoC. Actual exploitation requires // crafting proper netlink messages to trigger the rb_prev() NULL return // in nft_rbtree_gc_elem() during element insertion. static int create_nft_socket() { int fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_NETFILTER); if (fd < 0) { perror("socket"); return -1; } struct sockaddr_nl addr; memset(&addr, 0, sizeof(addr)); addr.nl_family = AF_NETLINK; if (bind(fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) { perror("bind"); close(fd); return -1; } return fd; } int main() { int nlfd = create_nft_socket(); if (nlfd < 0) return 1; printf("CVE-2023-53566 PoC - nft_set_rbtree null deref\n"); printf("Requires kernel < fixed version with nftables support\n"); // Steps to trigger: // 1. Create a nftables table // 2. Create a rbtree-type set within the table // 3. Add elements to the set in a specific order // 4. Set a short GC interval // 5. Add another element while GC is running // -> rb_prev() returns NULL -> null ptr deref -> kernel crash // The actual netlink message crafting is complex and requires // proper sequence of NFT_MSG_NEWTABLE, NFT_MSG_NEWSET, and // NFT_MSG_NEWSETELEM messages. close(nlfd); return 0; }

{"cve": {"id": "CVE-2023-53566", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2025-10-04T16:15:52.103", "lastModified": "2026-03-21T00:42:57.753", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nft_set_rbtree: fix null deref on element insertion\n\nThere is no guarantee that rb_prev() will not return NULL in nft_rbtree_gc_elem():\n\ngeneral protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN\nKASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]\n nft_add_set_elem+0x14b0/0x2990\n nf_tables_newsetelem+0x528/0xb30\n\nFurthermore, there is a possible use-after-free while iterating,\n'node' can be free'd so we need to cache the next value to use."}], "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": "CWE-476"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10.166", "versionEndExcluding": "5.10.181", "matchCriteriaId": "070E8660-956A-4689-B9A8-D695F0E7F645"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15.91", "versionEndExcluding": "5.15.113", "matchCriteriaId": "A3CF9954-4D8B-4BDF-BAB4-746E7C54C492"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1.9", "versionEndExcluding": "6.1.30", "matchCriteriaId": "7D56A580-DBF9-4DB5-B944-C518D206E060"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2.1", "versionEndExcluding": "6.3.4", "matchCriteriaId": "CF21E12D-BE44-4B69-8FF7-165E50EAF102"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:6.2:-:*:*:*:*:*:*", "matchCriteriaId": "3ADCCCEE-143A-4B48-9B2A-0CB97BD385DE"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:6.2:rc6:*:*:*:*:*:*", "matchCriteriaId": "4AB8D555-648E-4F2F-98BD-3E7F45BD12A8"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:6.2:rc7:*:*:*:*:*:*", "matchCriteriaId": "C64BDD9D-C663-4E75-AE06-356EDC392B82"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:6.2:rc8:*:*:*:*:*:*", "matchCriteriaId": "26544390-88E4-41CA-98BF-7BB1E9D4E243"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:6.4:rc1:*:*:*:*:*:*", "matchCriteriaId": "38BC6744-7D25-4C02-9966-B224CD071D30"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:6.4:rc2:*:*:*:*:*:*", "matchCriteriaId": "76061B41-CAE9-4467-BEDE-0FFC7956F2A1"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/3fa13203b6d90cc3a33af47b058739f92ab82eef", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/61ae320a29b0540c16931816299eb86bf2b66c08", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/899aa5638568abf5d69de7a7bb95e4615157375b", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/a337706c1fb35aac3f26b48aca80421bdbe1d33a", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/a836be60a3aabcedcd9c79f545d409ace1f20ba6", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/b76db53ee8802ee5683f8cb401d7e2ec6f9b3d56", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/ec5caa765f7f6960011c919c9aeb1467940421f6", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}