CVE-2026-45839 (GCVE-0-2026-45839)
Vulnerability from cvelistv5 – Published: 2026-05-27 09:24 – Updated: 2026-05-27 09:24
VLAI
Title
bpf: reject negative CO-RE accessor indices in bpf_core_parse_spec()
Summary
In the Linux kernel, the following vulnerability has been resolved:
bpf: reject negative CO-RE accessor indices in bpf_core_parse_spec()
CO-RE accessor strings are colon-separated indices that describe a path
from a root BTF type to a target field, e.g. "0:1:2" walks through
nested struct members. bpf_core_parse_spec() parses each component with
sscanf("%d"), so negative values like -1 are silently accepted. The
subsequent bounds checks (access_idx >= btf_vlen(t)) only guard the
upper bound and always pass for negative values because C integer
promotion converts the __u16 btf_vlen result to int, making the
comparison (int)(-1) >= (int)(N) false for any positive N.
When -1 reaches btf_member_bit_offset() it gets cast to u32 0xffffffff,
producing an out-of-bounds read far past the members array. A crafted
BPF program with a negative CO-RE accessor on any struct that exists in
vmlinux BTF (e.g. task_struct) crashes the kernel deterministically
during BPF_PROG_LOAD on any system with CONFIG_DEBUG_INFO_BTF=y
(default on major distributions). The bug is reachable with CAP_BPF:
BUG: unable to handle page fault for address: ffffed11818b6626
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
Oops: Oops: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 85 Comm: poc Not tainted 7.0.0-rc6 #18 PREEMPT(full)
RIP: 0010:bpf_core_parse_spec (tools/lib/bpf/relo_core.c:354)
RAX: 00000000ffffffff
Call Trace:
<TASK>
bpf_core_calc_relo_insn (tools/lib/bpf/relo_core.c:1321)
bpf_core_apply (kernel/bpf/btf.c:9507)
check_core_relo (kernel/bpf/verifier.c:19475)
bpf_check (kernel/bpf/verifier.c:26031)
bpf_prog_load (kernel/bpf/syscall.c:3089)
__sys_bpf (kernel/bpf/syscall.c:6228)
</TASK>
CO-RE accessor indices are inherently non-negative (struct member index,
array element index, or enumerator index), so reject them immediately
after parsing.
Severity
No CVSS data available.
Assigner
References
Impacted products
2 products
| Vendor | Product | Version | |
|---|---|---|---|
| Linux | Linux |
Affected:
ddc7c3042614e273044f698d2beab25cc3842d45 , < 3ff85ae79e1a74baeb916b78a63d821f6d19a994
(git)
Affected: ddc7c3042614e273044f698d2beab25cc3842d45 , < 36a9012f76ba8d9189ae56a1f8bb7c87c07a1f3a (git) Affected: ddc7c3042614e273044f698d2beab25cc3842d45 , < 76f2ebaf79a9ae6d0737b87f045fe769e425d78f (git) Affected: ddc7c3042614e273044f698d2beab25cc3842d45 , < 99dbab7b5a12d8f58d5b0aa2f7a1fe656a70f4b2 (git) Affected: ddc7c3042614e273044f698d2beab25cc3842d45 , < 1c22483a2c4bbf747787f328392ca3e68619c4dc (git) |
|
| Linux | Linux |
Affected:
5.4
Unaffected: 0 , < 5.4 (semver) Unaffected: 6.6.141 , ≤ 6.6.* (semver) Unaffected: 6.12.91 , ≤ 6.12.* (semver) Unaffected: 6.18.33 , ≤ 6.18.* (semver) Unaffected: 7.0.10 , ≤ 7.0.* (semver) Unaffected: 7.1-rc1 , ≤ * (original_commit_for_fix) |
{
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"status": "unaffected",
"version": "6.18.33",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "7.0.10",
"versionType": "semver"
},
{
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"status": "unaffected",
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"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: reject negative CO-RE accessor indices in bpf_core_parse_spec()\n\nCO-RE accessor strings are colon-separated indices that describe a path\nfrom a root BTF type to a target field, e.g. \"0:1:2\" walks through\nnested struct members. bpf_core_parse_spec() parses each component with\nsscanf(\"%d\"), so negative values like -1 are silently accepted. The\nsubsequent bounds checks (access_idx \u003e= btf_vlen(t)) only guard the\nupper bound and always pass for negative values because C integer\npromotion converts the __u16 btf_vlen result to int, making the\ncomparison (int)(-1) \u003e= (int)(N) false for any positive N.\n\nWhen -1 reaches btf_member_bit_offset() it gets cast to u32 0xffffffff,\nproducing an out-of-bounds read far past the members array. A crafted\nBPF program with a negative CO-RE accessor on any struct that exists in\nvmlinux BTF (e.g. task_struct) crashes the kernel deterministically\nduring BPF_PROG_LOAD on any system with CONFIG_DEBUG_INFO_BTF=y\n(default on major distributions). The bug is reachable with CAP_BPF:\n\n BUG: unable to handle page fault for address: ffffed11818b6626\n #PF: supervisor read access in kernel mode\n #PF: error_code(0x0000) - not-present page\n Oops: Oops: 0000 [#1] SMP KASAN NOPTI\n CPU: 0 UID: 0 PID: 85 Comm: poc Not tainted 7.0.0-rc6 #18 PREEMPT(full)\n RIP: 0010:bpf_core_parse_spec (tools/lib/bpf/relo_core.c:354)\n RAX: 00000000ffffffff\n Call Trace:\n \u003cTASK\u003e\n bpf_core_calc_relo_insn (tools/lib/bpf/relo_core.c:1321)\n bpf_core_apply (kernel/bpf/btf.c:9507)\n check_core_relo (kernel/bpf/verifier.c:19475)\n bpf_check (kernel/bpf/verifier.c:26031)\n bpf_prog_load (kernel/bpf/syscall.c:3089)\n __sys_bpf (kernel/bpf/syscall.c:6228)\n \u003c/TASK\u003e\n\nCO-RE accessor indices are inherently non-negative (struct member index,\narray element index, or enumerator index), so reject them immediately\nafter parsing."
}
],
"providerMetadata": {
"dateUpdated": "2026-05-27T09:24:37.855Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
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{
"url": "https://git.kernel.org/stable/c/3ff85ae79e1a74baeb916b78a63d821f6d19a994"
},
{
"url": "https://git.kernel.org/stable/c/36a9012f76ba8d9189ae56a1f8bb7c87c07a1f3a"
},
{
"url": "https://git.kernel.org/stable/c/76f2ebaf79a9ae6d0737b87f045fe769e425d78f"
},
{
"url": "https://git.kernel.org/stable/c/99dbab7b5a12d8f58d5b0aa2f7a1fe656a70f4b2"
},
{
"url": "https://git.kernel.org/stable/c/1c22483a2c4bbf747787f328392ca3e68619c4dc"
}
],
"title": "bpf: reject negative CO-RE accessor indices in bpf_core_parse_spec()",
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"cveId": "CVE-2026-45839",
"datePublished": "2026-05-27T09:24:37.855Z",
"dateReserved": "2026-05-13T15:03:33.077Z",
"dateUpdated": "2026-05-27T09:24:37.855Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-45839",
"date": "2026-05-28",
"epss": "0.00015",
"percentile": "0.03506"
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"nvd": "{\"cve\":{\"id\":\"CVE-2026-45839\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-05-27T11:16:23.247\",\"lastModified\":\"2026-05-27T14:48:03.013\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nbpf: reject negative CO-RE accessor indices in bpf_core_parse_spec()\\n\\nCO-RE accessor strings are colon-separated indices that describe a path\\nfrom a root BTF type to a target field, e.g. \\\"0:1:2\\\" walks through\\nnested struct members. bpf_core_parse_spec() parses each component with\\nsscanf(\\\"%d\\\"), so negative values like -1 are silently accepted. The\\nsubsequent bounds checks (access_idx \u003e= btf_vlen(t)) only guard the\\nupper bound and always pass for negative values because C integer\\npromotion converts the __u16 btf_vlen result to int, making the\\ncomparison (int)(-1) \u003e= (int)(N) false for any positive N.\\n\\nWhen -1 reaches btf_member_bit_offset() it gets cast to u32 0xffffffff,\\nproducing an out-of-bounds read far past the members array. A crafted\\nBPF program with a negative CO-RE accessor on any struct that exists in\\nvmlinux BTF (e.g. task_struct) crashes the kernel deterministically\\nduring BPF_PROG_LOAD on any system with CONFIG_DEBUG_INFO_BTF=y\\n(default on major distributions). The bug is reachable with CAP_BPF:\\n\\n BUG: unable to handle page fault for address: ffffed11818b6626\\n #PF: supervisor read access in kernel mode\\n #PF: error_code(0x0000) - not-present page\\n Oops: Oops: 0000 [#1] SMP KASAN NOPTI\\n CPU: 0 UID: 0 PID: 85 Comm: poc Not tainted 7.0.0-rc6 #18 PREEMPT(full)\\n RIP: 0010:bpf_core_parse_spec (tools/lib/bpf/relo_core.c:354)\\n RAX: 00000000ffffffff\\n Call Trace:\\n \u003cTASK\u003e\\n bpf_core_calc_relo_insn (tools/lib/bpf/relo_core.c:1321)\\n bpf_core_apply (kernel/bpf/btf.c:9507)\\n check_core_relo (kernel/bpf/verifier.c:19475)\\n bpf_check (kernel/bpf/verifier.c:26031)\\n bpf_prog_load (kernel/bpf/syscall.c:3089)\\n __sys_bpf (kernel/bpf/syscall.c:6228)\\n \u003c/TASK\u003e\\n\\nCO-RE accessor indices are inherently non-negative (struct member index,\\narray element index, or enumerator index), so reject them immediately\\nafter parsing.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/1c22483a2c4bbf747787f328392ca3e68619c4dc\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/36a9012f76ba8d9189ae56a1f8bb7c87c07a1f3a\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/3ff85ae79e1a74baeb916b78a63d821f6d19a994\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/76f2ebaf79a9ae6d0737b87f045fe769e425d78f\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/99dbab7b5a12d8f58d5b0aa2f7a1fe656a70f4b2\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
}
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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