CVE-2026-98151
Estado: Pendiente de análisisSin puntuar—
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix REG INVARIANTS VIOLATION on speculative pointer arithmetic
Take the following unprivileged program as an example:
Loading it triggers a verifier warning from reg_bounds_sanity_check():
What happens:
var_off and the 32-bit range must always be consistent. There are two ways to keep the snapshot consistent:
The whole point of sanitize_ptr_alu() is to insert a harmless masking sequence that keeps the access in bounds under speculation, so the state it snapshots should faithfully represent that.
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Take approach 2: move __mark_reg32_unbounded() to after sanitize_ptr_alu(), so the speculative snapshot keeps the pointer's original, consistent r32. The non-speculative path is unchanged: r32 is still blanked before the offset is applied and re-derived by reg_bounds_sync().
Detalles técnicos trazas, registros y código del informe original
r0 = bpf_map_lookup_elem(...) /* PTR_TO_MAP_VALUE, offset 0 */
...
14: r0 += r1 /* r1 is a bounded scalar */
15: r9 = r0
verifier bug: REG INVARIANTS VIOLATION (alu): const subreg tnum out
of sync with range bounds r64={.base=0x0, .size=0x0}
r32={.base=0x0, .size=0xffffffff} var_off=(0x0, 0x0)
1. Processing insn 14 (r0 += r1) in adjust_ptr_min_max_vals(), the new
offset is computed into dst_reg's var_off and 32/64-bit ranges.
2. Because pointer registers do not track 32-bit subregister bounds,
__mark_reg32_unbounded() first sets r32 to the full range; r32 is
re-derived from the offset at the end of the function by
reg_bounds_sync().
3. On the unprivileged path, sanitize_ptr_alu() is called and, via
sanitize_speculative_path() -> push_stack(), snapshots the current
register state and schedules the next instruction (insn 15) to be
verified directly as a speculative path.
4. That snapshot is taken between step 2 and the final reg_bounds_sync():
at this point dst_reg's var_off still holds the (const) original
offset while r32 has just been blanked to the full range, i.e. the two
are out of sync. When the speculative path later verifies insn 15
(r9 = r0), the inconsistent state reaches reg_bounds_sanity_check() and
trips the warning.
1. sync var_off and r32 before the snapshot so they match, or
2. leave r32 at its original (already consistent) value and blank it
only after the snapshot.CVSS
NVD no ha asignado puntuación CVSS a esta CVE (habitual desde el cambio de política de abril de 2026).
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.16%
- Percentil entre todas las CVEs puntuadas: 4
- Fecha de la puntuación: 1/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
Referencias
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-98151",
"cveTags": [],
"metrics": {},
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5f99f312bd3bedb3b266b0d26376a8c500cdc97f",
"lessThan": "21a681526c715aebb4f918b8c131583442d1b3d8",
"versionType": "git"
},
{
"status": "affected",
"version": "5f99f312bd3bedb3b266b0d26376a8c500cdc97f",
"lessThan": "d623a4a58bb238443505d5c2949d1182dcfc26b6",
"versionType": "git"
},
{
"status": "affected",
"version": "5f99f312bd3bedb3b266b0d26376a8c500cdc97f",
"lessThan": "9f9477ae73de9c5a28e8ab7000d8097b078faee4",
"versionType": "git"
},
{
"status": "affected",
"version": "5f99f312bd3bedb3b266b0d26376a8c500cdc97f",
"lessThan": "150aeba624e8b7cac51c39440d7e8e1fd11de9a0",
"versionType": "git"
}
],
"programFiles": [
"kernel/bpf/verifier.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.8"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.8",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.12.111",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.53",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.7",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3-rc2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"kernel/bpf/verifier.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-09-25T11:17:46.693",
"references": [
{
"url": "https://git.kernel.org/stable/c/150aeba624e8b7cac51c39440d7e8e1fd11de9a0",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/21a681526c715aebb4f918b8c131583442d1b3d8",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/9f9477ae73de9c5a28e8ab7000d8097b078faee4",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/d623a4a58bb238443505d5c2949d1182dcfc26b6",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Awaiting Analysis",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix REG INVARIANTS VIOLATION on speculative pointer arithmetic\n\nTake the following unprivileged program as an example:\n\n\tr0 = bpf_map_lookup_elem(...)\t/* PTR_TO_MAP_VALUE, offset 0 */\n\t...\n\t14: r0 += r1\t\t\t/* r1 is a bounded scalar */\n\t15: r9 = r0\n\nLoading it triggers a verifier warning from reg_bounds_sanity_check():\n\n\tverifier bug: REG INVARIANTS VIOLATION (alu): const subreg tnum out\n\tof sync with range bounds r64={.base=0x0, .size=0x0}\n\tr32={.base=0x0, .size=0xffffffff} var_off=(0x0, 0x0)\n\nWhat happens:\n\n1. Processing insn 14 (r0 += r1) in adjust_ptr_min_max_vals(), the new\n offset is computed into dst_reg's var_off and 32/64-bit ranges.\n\n2. Because pointer registers do not track 32-bit subregister bounds,\n __mark_reg32_unbounded() first sets r32 to the full range; r32 is\n re-derived from the offset at the end of the function by\n reg_bounds_sync().\n\n3. On the unprivileged path, sanitize_ptr_alu() is called and, via\n sanitize_speculative_path() -> push_stack(), snapshots the current\n register state and schedules the next instruction (insn 15) to be\n verified directly as a speculative path.\n\n4. That snapshot is taken between step 2 and the final reg_bounds_sync():\n at this point dst_reg's var_off still holds the (const) original\n offset while r32 has just been blanked to the full range, i.e. the two\n are out of sync. When the speculative path later verifies insn 15\n (r9 = r0), the inconsistent state reaches reg_bounds_sanity_check() and\n trips the warning.\n\nvar_off and the 32-bit range must always be consistent. There are two\nways to keep the snapshot consistent:\n\n 1. sync var_off and r32 before the snapshot so they match, or\n 2. leave r32 at its original (already consistent) value and blank it\n only after the snapshot.\n\nThe whole point of sanitize_ptr_alu() is to insert a harmless masking\nsequence that keeps the access in bounds under speculation, so the state\nit snapshots should faithfully represent that. Take approach 2: move\n__mark_reg32_unbounded() to after sanitize_ptr_alu(), so the speculative\nsnapshot keeps the pointer's original, consistent r32. The non-speculative\npath is unchanged: r32 is still blanked before the offset is applied and\nre-derived by reg_bounds_sync()."
}
],
"lastModified": "2026-09-30T14:10:59.253",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}