CVE-2026-93125 (GCVE-0-2026-93125)
Vulnerability from cvelistv5
Published
2026-09-17 16:11
Modified
2026-10-30 12:36
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
bpf: Reject rdonly/rdwr_buf_size kfunc arguments that exceed u32 max
check_kfunc_args() detects a kfunc argument named rdonly_buf_size or
rdwr_buf_size and stores reg->var_off.value into meta->r0_size, a u64,
and does not bound it. check_kfunc_call() later copies that value into
the returned register's mem_size field:
meta->r0_size = reg->var_off.value;
...
regs[BPF_REG_0].mem_size = meta.r0_size;
regs[BPF_REG_0].mem_size is u32. A constant whose upper 32 bits are set
gets truncated instead of causing a load-time rejection, so the verifier
records a PTR_TO_MEM register with an approximately 4 GiB mem_size for
whatever allocation the kfunc returned. A later access check against
that register uses the truncated, wrong bound.
Reject rdonly_buf_size/rdwr_buf_size values that exceed U32_MAX at the
point meta->r0_size is set.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: eb1f7f71c126c8fd50ea81af98f97c4b581ea4ae Version: eb1f7f71c126c8fd50ea81af98f97c4b581ea4ae Version: eb1f7f71c126c8fd50ea81af98f97c4b581ea4ae Version: eb1f7f71c126c8fd50ea81af98f97c4b581ea4ae Version: eb1f7f71c126c8fd50ea81af98f97c4b581ea4ae Version: eb1f7f71c126c8fd50ea81af98f97c4b581ea4ae |
||
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"kernel/bpf/verifier.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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{
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"versionType": "git"
},
{
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"status": "affected",
"version": "eb1f7f71c126c8fd50ea81af98f97c4b581ea4ae",
"versionType": "git"
},
{
"lessThan": "93a20b14f8627b2d3486e3ec1d3f2e7275a506ec",
"status": "affected",
"version": "eb1f7f71c126c8fd50ea81af98f97c4b581ea4ae",
"versionType": "git"
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{
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"status": "affected",
"version": "eb1f7f71c126c8fd50ea81af98f97c4b581ea4ae",
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{
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"status": "affected",
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]
},
{
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"product": "Linux",
"programFiles": [
"kernel/bpf/verifier.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.1"
},
{
"lessThan": "6.1",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.191",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.160",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.114",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.57",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"version": "7.2.6",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.1.191",
"versionStartIncluding": "6.1",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.6.160",
"versionStartIncluding": "6.1",
"vulnerable": true
},
{
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"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.57",
"versionStartIncluding": "6.1",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2.6",
"versionStartIncluding": "6.1",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.3",
"versionStartIncluding": "6.1",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"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-\u003evar_off.value into meta-\u003er0_size, a u64,\nand does not bound it. check_kfunc_call() later copies that value into\nthe returned register\u0027s mem_size field:\n\n meta-\u003er0_size = reg-\u003evar_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-\u003er0_size is set."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:L - check_kfunc_args() takes the oversized rdonly_buf_size/rdwr_buf_size from the BPF program\u0027s own constant (reg-\u003evar_off.value) on the local bpf(BPF_PROG_LOAD) path (bpf_prog_load \u2192 bpf_check \u2192 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-\u003ebpf_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 \u003e 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\u0027s actual object (prog_test_struct from get_mem, hid_bpf_get_data\u0027s ctx_kern-\u003edata, or an io_uring mapped region) and can oops or panic the kernel."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-10-30T12:36:03.562Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/00bb52be60da16cd5ead4eb9f8ddc9a66d003ff2"
},
{
"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"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-93125",
"datePublished": "2026-09-17T16:11:29.895Z",
"dateReserved": "2026-09-17T16:02:15.087Z",
"dateUpdated": "2026-10-30T12:36:03.562Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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