CVE-2026-98273 (GCVE-0-2026-98273)
Vulnerability from cvelistv5
Published
2026-10-06 08:45
Modified
2026-10-19 09:16
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
x86/kprobes: Fix crash when probing CS CALL instructions
When using eBPF to probe CS CALL instructions within a function,
a crash can be triggered.
The eBPF tool probes offset 257 of the __hrtimer_run_queues()
function:
<__hrtimer_run_queues+249>: nopl 0x0(%rax,%rax,1)
<__hrtimer_run_queues+254>: mov %r14,%rdi
<__hrtimer_run_queues+257>: cs call <__x86_indirect_thunk_r12>
<__hrtimer_run_queues+263>: mov %eax,%r12d
<__hrtimer_run_queues+266>: xchg %ax,%ax
<__hrtimer_run_queues+268>: mov %r13,%rdi
Which triggers this crash:
BUG: unable to handle page fault for address: 00000000000f41c9
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 0 P4D 0
Oops: 0002 [#1] SMP NOPTI
CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P
RIP: 0010:__hrtimer_run_queues+0x106/0x230
Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is
at the 6th byte of the above CS CALL instruction. Since the CS CALL
instruction occupies 6 bytes, the exception occurred in the middle of that
call instruction.
The root cause is that when using eBPF tools to probe in the middle of a
function, a kprobe with INT3 is used as the underlying implementation.
During single-step emulation of the original CALL instruction,
int3_emulate_call() assumes that the probed CALL instruction is 5 bytes
long. However, the actual CS-prefixed CALL instruction occupies 6 bytes,
so it constructs an incorrect exception return address. When the CPU
returns from the kprobe handler, the next instruction to be executed is at
the address of the last byte of that CS CALL instruction. Coincidentally,
starting from that address, the CPU fetches and decodes a completely
different instruction, which ultimately triggers a kernel crash.
Fix the issue by using the actual instruction length obtained from
the instruction decoder when constructing the exception return
address, rather than relying on the hardcoded CALL_INSN_SIZE macro.
[ mingo: Refined the changelog ]
References
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"arch/x86/include/asm/text-patching.h",
"arch/x86/kernel/alternative.c",
"arch/x86/kernel/kprobes/core.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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"versionType": "git"
},
{
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"status": "affected",
"version": "6256e668b7af9d81472e03c6a171630c08f8858a",
"versionType": "git"
},
{
"status": "affected",
"version": "ba7d1dae9fe866abe74bb1e849fb85983b7c4c37",
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},
{
"lessThan": "5.11",
"status": "affected",
"version": "5.10.190",
"versionType": "semver"
}
]
},
{
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"product": "Linux",
"programFiles": [
"arch/x86/include/asm/text-patching.h",
"arch/x86/kernel/alternative.c",
"arch/x86/kernel/kprobes/core.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "5.13"
},
{
"lessThan": "5.13",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.54",
"versionType": "semver"
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{
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"status": "unaffected",
"version": "7.2.8",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
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"nodes": [
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"cpeMatch": [
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.54",
"versionStartIncluding": "5.13",
"vulnerable": true
},
{
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"versionStartIncluding": "5.10.190",
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],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nx86/kprobes: Fix crash when probing CS CALL instructions\n\nWhen using eBPF to probe CS CALL instructions within a function,\na crash can be triggered.\n\nThe eBPF tool probes offset 257 of the __hrtimer_run_queues()\nfunction:\n\n\u003c__hrtimer_run_queues+249\u003e: nopl 0x0(%rax,%rax,1)\n\u003c__hrtimer_run_queues+254\u003e: mov %r14,%rdi\n\u003c__hrtimer_run_queues+257\u003e: cs call \u003c__x86_indirect_thunk_r12\u003e\n\u003c__hrtimer_run_queues+263\u003e: mov %eax,%r12d\n\u003c__hrtimer_run_queues+266\u003e: xchg %ax,%ax\n\u003c__hrtimer_run_queues+268\u003e: mov %r13,%rdi\n\nWhich triggers this crash:\n\n BUG: unable to handle page fault for address: 00000000000f41c9\n #PF: supervisor write access in kernel mode\n #PF: error_code(0x0002) - not-present page\n PGD 0 P4D 0\n Oops: 0002 [#1] SMP NOPTI\n CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P\n RIP: 0010:__hrtimer_run_queues+0x106/0x230\n\nNote that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is\nat the 6th byte of the above CS CALL instruction. Since the CS CALL\ninstruction occupies 6 bytes, the exception occurred in the middle of that\ncall instruction.\n\nThe root cause is that when using eBPF tools to probe in the middle of a\nfunction, a kprobe with INT3 is used as the underlying implementation.\n\nDuring single-step emulation of the original CALL instruction,\nint3_emulate_call() assumes that the probed CALL instruction is 5 bytes\nlong. However, the actual CS-prefixed CALL instruction occupies 6 bytes,\nso it constructs an incorrect exception return address. When the CPU\nreturns from the kprobe handler, the next instruction to be executed is at\nthe address of the last byte of that CS CALL instruction. Coincidentally,\nstarting from that address, the CPU fetches and decodes a completely\ndifferent instruction, which ultimately triggers a kernel crash.\n\nFix the issue by using the actual instruction length obtained from\nthe instruction decoder when constructing the exception return\naddress, rather than relying on the hardcoded CALL_INSN_SIZE macro.\n\n[ mingo: Refined the changelog ]"
}
],
"providerMetadata": {
"dateUpdated": "2026-10-19T09:16:44.960Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/cfc1af3d054aaabee08f1f77c441b3533b082869"
},
{
"url": "https://git.kernel.org/stable/c/d8c6a18c0552135cbf0c696c9019b2979d0862c9"
},
{
"url": "https://git.kernel.org/stable/c/a5f7a5bb3b7f28ba7e4fa246775b29a0e5537255"
}
],
"title": "x86/kprobes: Fix crash when probing CS CALL instructions",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-98273",
"datePublished": "2026-10-06T08:45:34.645Z",
"dateReserved": "2026-09-25T10:25:14.334Z",
"dateUpdated": "2026-10-19T09:16:44.960Z",
"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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