{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-93125", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-17T16:02:15.087Z", "datePublished": "2026-09-17T16:11:29.895Z", "dateUpdated": "2026-10-21T12:51:58.749Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-21T12:51:58.749Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Reject rdonly/rdwr_buf_size kfunc arguments that exceed u32 max\n\ncheck_kfunc_args() detects a kfunc argument named rdonly_buf_size or\nrdwr_buf_size and stores reg->var_off.value into meta->r0_size, a u64,\nand does not bound it. check_kfunc_call() later copies that value into\nthe returned register's mem_size field:\n\n meta->r0_size = reg->var_off.value;\n ...\n regs[BPF_REG_0].mem_size = meta.r0_size;\n\nregs[BPF_REG_0].mem_size is u32. A constant whose upper 32 bits are set\ngets truncated instead of causing a load-time rejection, so the verifier\nrecords a PTR_TO_MEM register with an approximately 4 GiB mem_size for\nwhatever allocation the kfunc returned. A later access check against\nthat register uses the truncated, wrong bound.\n\nReject rdonly_buf_size/rdwr_buf_size values that exceed U32_MAX at the\npoint meta->r0_size is 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 - check_kfunc_args() takes the oversized rdonly_buf_size/rdwr_buf_size from the BPF program's own constant (reg->var_off.value) on the local bpf(BPF_PROG_LOAD) path (bpf_prog_load → bpf_check → check_kfunc_call). That immediate is not a field of a received packet or a ksmbd/nfsd message.\nAC:L - The attacker picks a 64-bit immediate with upper bits set (e.g. ~0ULL as in hid_rdesc_fixup_get_data_overflow) as the rdonly_buf_size/rdwr_buf_size argument; tnum_is_const succeeds and regs[BPF_REG_0].mem_size = meta.r0_size truncates deterministically, with no race or layout outside their control.\nPR:L - do_check_common() rejects BPF_PSEUDO_KFUNC_CALL unless env->bpf_capable, which bpf_check() sets from bpf_token_capable(token, CAP_BPF). CAP_BPF is a reduced capability and is delegable into a user namespace via a BPF token, so init-namespace root is not required.\nUI:N - The attacker loads the crafted program with bpf(BPF_PROG_LOAD) and runs it themselves via BPF_PROG_TEST_RUN or by attaching their own HID-BPF/io_uring struct_ops. No separate victim action such as mounting an image is required.\nS:U - The truncated PTR_TO_MEM mem_size lets the verified program read and write host kernel memory, which is a standard kernel privilege escalation in the same authority. It does not cross a KVM/Xen, IOMMU, or guest-to-host boundary.\nC:H - check_kfunc_call() copies the truncated r0_size into a PTR_TO_MEM register, so check_mem_region_access() allows loads of up to ~4 GiB. bpf_kfunc_call_test_get_rdonly_mem takes const int rdonly_buf_size: a value such as 0x1FFFFFFFF becomes -1, the size > 8 check fails open, and the 8-byte prog_test_ref_kfunc is treated as a 4 GiB readable buffer.\nI:H - rdwr_buf_size kfuncs (bpf_kfunc_call_test_get_rdwr_mem, hid_bpf_get_data, bpf_io_uring_get_region) mark R0 as writable PTR_TO_MEM. The same truncated mem_size lets check_mem_region_access() accept stores past the real object, which is an arbitrary kernel write.\nA:H - Those verifier-allowed out-of-bounds loads and stores overrun the kfunc's actual object (prog_test_struct from get_mem, hid_bpf_get_data's ctx_kern->data, or an io_uring mapped region) and can oops or panic the kernel." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/bpf/verifier.c" ], "versions": [ { "version": "eb1f7f71c126c8fd50ea81af98f97c4b581ea4ae", "lessThan": "2147065d3a4e1d5d42ae553fef165f17ec5e0e79", "status": "affected", "versionType": "git" }, { "version": "eb1f7f71c126c8fd50ea81af98f97c4b581ea4ae", "lessThan": "b6ac0b5732047d43172b9dfbe6b57b9b8de303c2", "status": "affected", "versionType": "git" }, { "version": "eb1f7f71c126c8fd50ea81af98f97c4b581ea4ae", "lessThan": "93a20b14f8627b2d3486e3ec1d3f2e7275a506ec", "status": "affected", "versionType": "git" }, { "version": "eb1f7f71c126c8fd50ea81af98f97c4b581ea4ae", "lessThan": "56a3846830ac95a472297d0cbba75cbff29540bb", "status": "affected", "versionType": "git" }, { "version": "eb1f7f71c126c8fd50ea81af98f97c4b581ea4ae", "lessThan": "2aaf67f0516fde29620d0edfc29c01b9ea7ad430", "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/verifier.c" ], "versions": [ { "version": "6.1", "status": "affected" }, { "version": "0", "lessThan": "6.1", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.160", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.114", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.57", "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": "6.1", "versionEndExcluding": "6.6.160" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1", "versionEndExcluding": "6.12.114" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1", "versionEndExcluding": "6.18.57" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1", "versionEndExcluding": "7.2.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/2147065d3a4e1d5d42ae553fef165f17ec5e0e79" }, { "url": "https://git.kernel.org/stable/c/b6ac0b5732047d43172b9dfbe6b57b9b8de303c2" }, { "url": "https://git.kernel.org/stable/c/93a20b14f8627b2d3486e3ec1d3f2e7275a506ec" }, { "url": "https://git.kernel.org/stable/c/56a3846830ac95a472297d0cbba75cbff29540bb" }, { "url": "https://git.kernel.org/stable/c/2aaf67f0516fde29620d0edfc29c01b9ea7ad430" } ], "title": "bpf: Reject rdonly/rdwr_buf_size kfunc arguments that exceed u32 max", "x_generator": { "engine": "bippy-1.2.0" } } } }