{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-74715", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.928Z", "datePublished": "2026-08-22T15:33:10.262Z", "dateUpdated": "2026-10-16T19:16:11.506Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-15T10:09:22.663Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix netns reference imbalance in conntrack kfuncs\n\nThe opts argument of the BPF conntrack kfuncs can point to a shared\nmap value. __bpf_nf_ct_lookup() and __bpf_nf_ct_alloc_entry() read\nopts->netns_id separately when acquiring and releasing the network\nnamespace reference.\n\nThe reference imbalance can occur as follows:\n\n CPU 0 CPU 1\n read opts->netns_id (-1)\n skip get_net_ns_by_id()\n write opts->netns_id (id)\n read opts->netns_id (id)\n put_net(net) /* no matching get */\n\nThe reverse transition leaks the reference. Repeating the unmatched put\ncan destroy a live namespace and crash later users.\n\nThe kernel reported:\n\n Oops: general protection fault, probably for non-canonical address\n KASAN: null-ptr-deref in range [0x00000000000000e8-0x00000000000000ef]\n RIP: 0010:bpf_prog_test_run_xdp+0x52c/0x1700\n Call Trace:\n __sys_bpf+0x1662/0x50c0\n __x64_sys_bpf+0x73/0xb0\n do_syscall_64+0xf9/0x540\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n Kernel panic - not syncing: Fatal exception\n\nSnapshot every input field of opts with READ_ONCE() before validating or\nusing it. The netns_id snapshot keeps the namespace get/put pair\nbalanced, while the other snapshots keep the remaining options from\nchanging partway through an invocation. The individual reads can still\nobserve an inconsistent combination during a concurrent update, but each\nselected field value remains stable for that invocation." } ], "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 bug is in BPF conntrack kfuncs reached only via the bpf() syscall (load, BPF_PROG_TEST_RUN, or attached XDP/TC programs), not from remote packet handling alone; kernel guidance classifies BPF as Local.\nAC:L - Exploitation needs a race on opts->netns_id in a shared BPF map value, but the attacker authors the program, drives concurrent bpf_map_update_elem and kfunc calls, and can pin threads to different CPUs to win the race reliably.\nPR:L - Triggering bpf_xdp_ct_lookup/bpf_skb_ct_lookup requires loading XDP or TC-BPF programs, which needs CAP_BPF and CAP_NET_ADMIN; both are obtainable by an unprivileged user inside a user/network namespace via unshare.\nUI:N - No victim interaction is required; the attacker loads their own BPF program, supplies map-backed opts, and runs concurrent test-run or traffic to trigger the refcount imbalance themselves.\nS:U - Impact is premature destruction of a live network namespace and kernel crashes within the same kernel security domain; it does not cross a VM, container-to-host, or IOMMU boundary.\nC:H - Repeated unmatched put_net() can drop a live namespace refcount to zero and free it while still in use, creating a net-namespace use-after-free that can expose freed kernel memory and enable information disclosure.\nI:H - The refcount corruption can destroy active network namespaces and corrupt kernel networking state; such lifetime bugs are memory corruption primitives that can be leveraged for arbitrary kernel modification or control-flow hijacking.\nA:H - The fix commit documents a reproduced general protection fault and kernel panic in bpf_prog_test_run_xdp from a null-ptr-deref after the namespace is destroyed, confirming complete system availability loss." } ] } ], "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_bpf.c" ], "versions": [ { "version": "aed8ee7feb44b6537af1e0b4f03365d42928be38", "lessThan": "4af94462c0ca2187a02a1a6641020ae888c74d5c", "status": "affected", "versionType": "git" }, { "version": "aed8ee7feb44b6537af1e0b4f03365d42928be38", "lessThan": "e5e060eb63d10b41ab60fd955649479d99b38210", "status": "affected", "versionType": "git" }, { "version": "aed8ee7feb44b6537af1e0b4f03365d42928be38", "lessThan": "fdeba03fea78407a8c52faa99177c9f7f29f90eb", "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_bpf.c" ], "versions": [ { "version": "6.0", "status": "affected" }, { "version": "0", "lessThan": "6.0", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.57", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.9", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "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": "6.0", "versionEndExcluding": "6.18.57" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "7.1.9" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/4af94462c0ca2187a02a1a6641020ae888c74d5c" }, { "url": "https://git.kernel.org/stable/c/e5e060eb63d10b41ab60fd955649479d99b38210" }, { "url": "https://git.kernel.org/stable/c/fdeba03fea78407a8c52faa99177c9f7f29f90eb" } ], "title": "bpf: Fix netns reference imbalance in conntrack kfuncs", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2026-74715", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "total" } ], "version": "2.0.3", "timestamp": "2026-10-16T19:15:29.946901Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T19:16:11.506Z" } } ] } }