{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2023-53619", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-10-07T15:16:59.655Z", "datePublished": "2025-10-07T15:19:26.003Z", "dateUpdated": "2026-08-05T09:15:10.461Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T09:15:10.461Z" }, "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": [ { "cvssV3_1": { "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" }, "scenarios": [ { "lang": "en", "value": "AV:L - The trigger is a local netlink/setsockopt operation (nftables ct helper object or iptables `-j CT --helper`) that drives conntrack-helper module autoloading, or a direct module load; no network-facing code path reaches `nf_conntrack_helper_register()`.\nAC:L - Per CVSS 3.1 §2.1.2, the base metrics are scored with the vulnerable component in its vulnerable configuration (built-in conntrack whose init failed, which is deterministic per boot on affected builds); in that state the attacker triggers `nf_conntrack_helper_register()` on demand and repeatably by naming different helpers, with no race or unknowable state to win.\nPR:L - An unprivileged local user obtains CAP_NET_ADMIN via `unshare -Urn`, since nfnetlink/nftables gates only on `netlink_net_capable(skb, CAP_NET_ADMIN)` and `__request_module()` performs no capability check, so `nft_ct_helper_obj_init()` autoloads the helper module that hits the dangling hash.\nUI:N - No victim action is needed; the attacker performs the entire sequence itself in its own network/user namespace.\nS:U - The corruption is confined to kernel memory within the same security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The bucket walk dereferences attacker-controlled pointers from the reallocated page (`strcmp(cur->name, me->name)`) giving an arbitrary-read/oracle primitive, and `rcu_assign_pointer(h->first, n)` writes a module `.data` pointer into memory the attacker can spray and read back, defeating KASLR.\nI:H - `WRITE_ONCE(first->pprev, &n->next)` in `hlist_add_head_rcu()` writes a known kernel pointer to an address fully controlled by the attacker-sprayed contents of the freed page — a write-what/where primitive suitable for control-flow hijack.\nA:H - Use-after-free on a freed page walked as an hlist reliably causes oops/panic or the \"random memory corruption\" the fix's author describes, taking down the kernel." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/netfilter/nf_conntrack_helper.c" ], "versions": [ { "version": "12f7a505331e6b2754684b509f2ac8f0011ce644", "lessThan": "4ee69c91cb8f9ca144bc0861969e5a1a3c6152a7", "status": "affected", "versionType": "git" }, { "version": "12f7a505331e6b2754684b509f2ac8f0011ce644", "lessThan": "00716f25f9697d02a0d9bd622575c7c7321ba3d0", "status": "affected", "versionType": "git" }, { "version": "12f7a505331e6b2754684b509f2ac8f0011ce644", "lessThan": "61c7a5256543ae7d24cd9d21853d514c8632e1e9", "status": "affected", "versionType": "git" }, { "version": "12f7a505331e6b2754684b509f2ac8f0011ce644", "lessThan": "8289d422f5e484efe4a565fe18e862ecd621c175", "status": "affected", "versionType": "git" }, { "version": "12f7a505331e6b2754684b509f2ac8f0011ce644", "lessThan": "6f03ce2f1abcb9f9d0511e3659ca6eb60e39f566", "status": "affected", "versionType": "git" }, { "version": "12f7a505331e6b2754684b509f2ac8f0011ce644", "lessThan": "05561f822f27b9fa88fa5504ddec34bf38833034", "status": "affected", "versionType": "git" }, { "version": "12f7a505331e6b2754684b509f2ac8f0011ce644", "lessThan": "fce5cc7cbd4b92f979bf02c9ec5fb69aaeba92d7", "status": "affected", "versionType": "git" }, { "version": "12f7a505331e6b2754684b509f2ac8f0011ce644", "lessThan": "6eef7a2b933885a17679eb8ed0796ddf0ee5309b", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/netfilter/nf_conntrack_helper.c" ], "versions": [ { "version": "3.6", "status": "affected" }, { "version": "0", "lessThan": "3.6", "status": "unaffected", "versionType": "semver" }, { "version": "4.14.322", "lessThanOrEqual": "4.14.*", "status": "unaffected", "versionType": "semver" }, { "version": "4.19.291", "lessThanOrEqual": "4.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.251", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.188", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.121", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.39", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.4.4", "lessThanOrEqual": "6.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.5", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.6", "versionEndExcluding": "4.14.322" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.6", "versionEndExcluding": "4.19.291" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.6", "versionEndExcluding": "5.4.251" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.6", "versionEndExcluding": "5.10.188" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.6", "versionEndExcluding": "5.15.121" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.6", "versionEndExcluding": "6.1.39" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.6", "versionEndExcluding": "6.4.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.6", "versionEndExcluding": "6.5" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/4ee69c91cb8f9ca144bc0861969e5a1a3c6152a7" }, { "url": "https://git.kernel.org/stable/c/00716f25f9697d02a0d9bd622575c7c7321ba3d0" }, { "url": "https://git.kernel.org/stable/c/61c7a5256543ae7d24cd9d21853d514c8632e1e9" }, { "url": "https://git.kernel.org/stable/c/8289d422f5e484efe4a565fe18e862ecd621c175" }, { "url": "https://git.kernel.org/stable/c/6f03ce2f1abcb9f9d0511e3659ca6eb60e39f566" }, { "url": "https://git.kernel.org/stable/c/05561f822f27b9fa88fa5504ddec34bf38833034" }, { "url": "https://git.kernel.org/stable/c/fce5cc7cbd4b92f979bf02c9ec5fb69aaeba92d7" }, { "url": "https://git.kernel.org/stable/c/6eef7a2b933885a17679eb8ed0796ddf0ee5309b" } ], "title": "netfilter: conntrack: Avoid nf_ct_helper_hash uses after free", "x_generator": { "engine": "bippy-1.2.0" } } } }