{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-98378", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.345Z", "datePublished": "2026-10-09T07:34:18.626Z", "dateUpdated": "2026-10-24T14:08:37.091Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-24T14:08:37.091Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Skip unsettled links in link iterator\n\nbpf_link_prime() inserts a link into link_idr before anon_inode_getfile()\nsucceeds and before bpf_link_settle() publishes the ID in link->id.\nbpf_link_by_id() treats such an ID-zero link as unsettled, but the link\niterator takes a reference without this check.\n\nIf anon_inode_getfile() then fails, the creator removes the ID and frees\nits still-private link directly. The iterator is left with a dangling\nreference and its next bpf_link_put() accesses freed memory.\n\nTreat ID-zero entries as transient in bpf_link_get_curr_or_next(), just as\nbpf_link_by_id() does.\n\n BUG: KASAN: slab-use-after-free in bpf_link_put\n Write of size 8 by task exp/384\n Call Trace:\n bpf_link_put kernel/bpf/syscall.c:3372\n bpf_link_seq_next kernel/bpf/link_iter.c:33\n bpf_seq_read kernel/bpf/bpf_iter.c:158\n vfs_read fs/read_write.c:572\n ksys_read fs/read_write.c:716\n do_syscall_64 arch/x86/entry/syscall_64.c:84\n entry_SYSCALL_64_after_hwframe arch/x86/entry/entry_64.S:121\n Kernel panic - not syncing: KASAN: panic_on_warn set ..." } ], "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 - Both required paths are local: bpf(BPF_LINK_CREATE/BPF_ITER_CREATE) prepares the bpf_link iterator, and read() reaches bpf_seq_read() -> bpf_link_seq_next() -> the patched bpf_link_get_curr_or_next(); no network data enters this state.\nAC:L - The attacker can fill fs.file-max so anon_inode_getfile() returns -ENFILE, then run the iterator reader and repeated BPF_LINK_CREATE calls concurrently, controlling both sides of the IDR insert/remove race.\nPR:L - BPF_PROG_LOAD for BPF_PROG_TYPE_TRACING/BPF_TRACE_ITER requires CAP_BPF and CAP_PERFMON, but bpf_token_capable() accepts them in a delegated bpffs token's user namespace; this permits a namespace-root local user, while a bare user namespace does not.\nUI:N - After preparing the iterator and program FDs, the attacking process itself issues read() and concurrent BPF_LINK_CREATE calls; no victim action is required.\nS:U - bpf_link_get_curr_or_next() leaves a dangling object inside the same host kernel that services the BPF syscalls; it crosses no guest/host, IOMMU, or separate security authority boundary.\nC:H - The iterator retains a freed struct bpf_link pointer; reclaiming that slab object makes later bpf_link_put()/bpf_link_free() consume attacker-influenced refcnt, ops, and prog fields, supporting kernel-memory disclosure.\nI:H - bpf_link_put() performs atomic64_dec_and_test() on the freed object's first eight bytes and can initialize and queue its reclaimed work_struct, so controlled reuse supports arbitrary corruption or control-flow hijacking.\nA:H - The demonstrated read() path reaches bpf_link_seq_next() and bpf_link_put() after the link is freed, producing a KASAN use-after-free and kernel panic; the same stale write can crash a non-KASAN kernel." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/bpf/syscall.c" ], "versions": [ { "version": "9f88361273082825d9f0d13a543d49f9fa0d44a8", "lessThan": "68930f8d40ab4c10ca3b019f076136758fd100a8", "status": "affected", "versionType": "git" }, { "version": "9f88361273082825d9f0d13a543d49f9fa0d44a8", "lessThan": "c251ed48bd9063cf7de6049421e78b6de989060f", "status": "affected", "versionType": "git" }, { "version": "9f88361273082825d9f0d13a543d49f9fa0d44a8", "lessThan": "798a61edbc436cacdb659927d067368eeb1e30e2", "status": "affected", "versionType": "git" }, { "version": "9f88361273082825d9f0d13a543d49f9fa0d44a8", "lessThan": "6e271f093d15d323f42de26f66556af53fa8e19f", "status": "affected", "versionType": "git" }, { "version": "9f88361273082825d9f0d13a543d49f9fa0d44a8", "lessThan": "87ce4b53b7436b50fc984f0a6afaf77f68ac5573", "status": "affected", "versionType": "git" }, { "version": "9f88361273082825d9f0d13a543d49f9fa0d44a8", "lessThan": "50e80e2bb5e2be8515205b9c496b9640ddefa434", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/bpf/syscall.c" ], "versions": [ { "version": "5.19", "status": "affected" }, { "version": "0", "lessThan": "5.19", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.189", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.158", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.112", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.55", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.9", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "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": "5.19", "versionEndExcluding": "6.1.189" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "6.6.158" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "6.12.112" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "6.18.55" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "7.2.9" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/68930f8d40ab4c10ca3b019f076136758fd100a8" }, { "url": "https://git.kernel.org/stable/c/c251ed48bd9063cf7de6049421e78b6de989060f" }, { "url": "https://git.kernel.org/stable/c/798a61edbc436cacdb659927d067368eeb1e30e2" }, { "url": "https://git.kernel.org/stable/c/6e271f093d15d323f42de26f66556af53fa8e19f" }, { "url": "https://git.kernel.org/stable/c/87ce4b53b7436b50fc984f0a6afaf77f68ac5573" }, { "url": "https://git.kernel.org/stable/c/50e80e2bb5e2be8515205b9c496b9640ddefa434" } ], "title": "bpf: Skip unsettled links in link iterator", "x_generator": { "engine": "bippy-1.2.0" } } } }