{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-90392", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.810Z", "datePublished": "2026-09-17T16:09:25.738Z", "dateUpdated": "2026-10-19T09:02:56.602Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T09:02:56.602Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix potential UAF when reading bpf link info\n\nIn bpf_link_show_fdinfo and bpf_link_get_info_by_fd, link->prog is\naccessed without holding any locks. If the prog is concurrently replaced\nvia bpf_link_update, the old prog can be freed, leading to a potential\nUAF issue.\n\nFix this by accessing link->prog under RCU protection to safely fetch\nthe pointer and guarantee its lifetime while reading its fields." } ], "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 dangling link->prog is read from the local bpf(2) BPF_OBJ_GET_INFO_BY_FD command (bpf_obj_get_info_by_fd()->bpf_link_get_info_by_fd()) or from bpf_link_show_fdinfo() when reading /proc/self/fdinfo on a bpf_link fd; neither path takes the malformed state from a network protocol.\nAC:L - The attacker owns both sides: one thread issues BPF_LINK_UPDATE so link_update() runs cgroup_bpf_replace()/tcx_link_update()/sock_map_link_update_prog() which xchg(&link->prog) and bpf_prog_put() the old program, while another thread they control races bpf_link_get_info_by_fd() or bpf_link_show_fdinfo(), which sleeps in seq_printf after capturing the pointer.\nPR:L - Creating a replaceable link requires bpf_prog_load() of a type whose ops implement update_prog (CGROUP_SKB, SCHED_CLS, SK_SKB, XDP, FLOW_DISSECTOR) plus BPF_LINK_CREATE; those paths require bpf_token_capable(CAP_BPF) and usually CAP_NET_ADMIN (CGROUP_SKB attach also checks it in bpf_prog_attach_check_attach_type), which a BPF token delegates into a user namespace.\nUI:N - The attacker loads two programs, BPF_LINK_CREATE the first as a cgroup/tcx/sockmap/xdp/netns link, closes the old program fd so the link holds the last ref, then races BPF_LINK_UPDATE against BPF_OBJ_GET_INFO_BY_FD or fdinfo in their own process; no other user action is required.\nS:U - The use-after-free is of the replaced bpf_prog inside bpf_link_get_info_by_fd()/bpf_link_show_fdinfo() on the host kernel; impact is local kernel memory corruption and privilege escalation, not a VM, IOMMU, or other authority-boundary cross.\nC:H - After the concurrent bpf_prog_put(), bpf_link_get_info_by_fd() reads prog->aux->id and bpf_link_show_fdinfo() copies prog->tag then aux->id from the freed bpf_prog; __bpf_prog_free() kfree()s the kmalloc bpf_prog_aux, so reclaiming that object turns the dangling aux pointer into an arbitrary kernel read.\nI:H - The same bpf_prog/bpf_prog_aux use-after-free after cgroup_bpf_replace() (or tcx/sockmap/xdp/netns update_prog) lets the attacker spray the freed kmalloc aux and vmalloc prog; kernel heap UAF of those objects yields write and control-flow hijack primitives.\nA:H - bpf_link_get_info_by_fd() and bpf_link_show_fdinfo() dereference the freed bpf_prog and prog->aux after BPF_LINK_UPDATE drops the last ref via bpf_prog_put(); a recycled or poisoned aux pointer causes a kernel oops." } ] } ], "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": "0c991ebc8c69d29b7fc44db17075c5aa5253e2ab", "lessThan": "a5c936ac904767fc1d943d40b0308bcb2ae2509b", "status": "affected", "versionType": "git" }, { "version": "0c991ebc8c69d29b7fc44db17075c5aa5253e2ab", "lessThan": "d7d7208e2603b45724b684f4df73904fb347741e", "status": "affected", "versionType": "git" }, { "version": "0c991ebc8c69d29b7fc44db17075c5aa5253e2ab", "lessThan": "85cf991c881e7198be32be05a9daa2625390c8b3", "status": "affected", "versionType": "git" }, { "version": "0c991ebc8c69d29b7fc44db17075c5aa5253e2ab", "lessThan": "79347e42cfbc9e78872922e8f08a70609c9af82f", "status": "affected", "versionType": "git" }, { "version": "0c991ebc8c69d29b7fc44db17075c5aa5253e2ab", "lessThan": "863f3ddd0b8ac65abfb50d3be0869268ac0e277b", "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": "5.7", "status": "affected" }, { "version": "0", "lessThan": "5.7", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.157", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.110", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.52", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.6", "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": "5.7", "versionEndExcluding": "6.6.157" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.12.110" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.18.52" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "7.2.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/a5c936ac904767fc1d943d40b0308bcb2ae2509b" }, { "url": "https://git.kernel.org/stable/c/d7d7208e2603b45724b684f4df73904fb347741e" }, { "url": "https://git.kernel.org/stable/c/85cf991c881e7198be32be05a9daa2625390c8b3" }, { "url": "https://git.kernel.org/stable/c/79347e42cfbc9e78872922e8f08a70609c9af82f" }, { "url": "https://git.kernel.org/stable/c/863f3ddd0b8ac65abfb50d3be0869268ac0e277b" } ], "title": "bpf: Fix potential UAF when reading bpf link info", "x_generator": { "engine": "bippy-1.2.0" } } } }