CVE-2026-98219 (GCVE-0-2026-98219)
Vulnerability from cvelistv5
Published
2026-10-06 08:44
Modified
2026-10-19 09:15
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
sched_ext: Close the pre-enable ops error claim window
scx_alloc_and_add_sched() publishes ops->priv before
scx_root_enable_workfn() switches the state to SCX_ENABLING. An error
claimed via scx_bpf_error_bstr() from an associated BPF program in that
window is consumed by scx_disable_workfn(), which takes the pre-enable
shortcut in scx_root_disable(). The shortcut returns without any teardown
and restores SCX_DISABLED with an unconditional scx_set_enable_state() xchg
racing the enable workfn's own transition. The enable then completes with
the claim consumed: the scheduler stays up but can never be disabled again,
and bpf_scx_unreg() frees it while still in use, resulting in a
use-after-free. Both WARN_ON_ONCE()s fire back to back:
WARNING: kernel/sched/ext/ext.c:7522 at
scx_root_enable_workfn+0xeec/0x1be0, CPU#3: scx_enable_help/276
WARNING: kernel/sched/ext/ext.c:6398 at scx_root_disable+0xb50/0xdb8,
CPU#0: sched_ext_helpe/664
scx_root_enable_workfn() switches to SCX_ENABLING before the scheduler
allocation, so ops->priv is never visible while SCX_DISABLED. The allocation
failure path restores SCX_DISABLED.
References
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"kernel/sched/ext/ext.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "959c66dc4a915be306c35691095c787c61dc7df9",
"status": "affected",
"version": "105dcd005be2ac1d5541921db8feb1d0f98d59d5",
"versionType": "git"
},
{
"lessThan": "c7a1c6e8004ab12a9c9bfdcb603f60f9bf4a3cee",
"status": "affected",
"version": "105dcd005be2ac1d5541921db8feb1d0f98d59d5",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"kernel/sched/ext/ext.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "7.1"
},
{
"lessThan": "7.1",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"version": "7.2.8",
"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": "7.2.8",
"versionStartIncluding": "7.1",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.3",
"versionStartIncluding": "7.1",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Close the pre-enable ops error claim window\n\nscx_alloc_and_add_sched() publishes ops-\u003epriv before\nscx_root_enable_workfn() switches the state to SCX_ENABLING. An error\nclaimed via scx_bpf_error_bstr() from an associated BPF program in that\nwindow is consumed by scx_disable_workfn(), which takes the pre-enable\nshortcut in scx_root_disable(). The shortcut returns without any teardown\nand restores SCX_DISABLED with an unconditional scx_set_enable_state() xchg\nracing the enable workfn\u0027s own transition. The enable then completes with\nthe claim consumed: the scheduler stays up but can never be disabled again,\nand bpf_scx_unreg() frees it while still in use, resulting in a\nuse-after-free. Both WARN_ON_ONCE()s fire back to back:\n\n WARNING: kernel/sched/ext/ext.c:7522 at\n scx_root_enable_workfn+0xeec/0x1be0, CPU#3: scx_enable_help/276\n\n WARNING: kernel/sched/ext/ext.c:6398 at scx_root_disable+0xb50/0xdb8,\n CPU#0: sched_ext_helpe/664\n\nscx_root_enable_workfn() switches to SCX_ENABLING before the scheduler\nallocation, so ops-\u003epriv is never visible while SCX_DISABLED. The allocation\nfailure path restores SCX_DISABLED."
}
],
"providerMetadata": {
"dateUpdated": "2026-10-19T09:15:51.341Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/959c66dc4a915be306c35691095c787c61dc7df9"
},
{
"url": "https://git.kernel.org/stable/c/c7a1c6e8004ab12a9c9bfdcb603f60f9bf4a3cee"
}
],
"title": "sched_ext: Close the pre-enable ops error claim window",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-98219",
"datePublished": "2026-10-06T08:44:54.943Z",
"dateReserved": "2026-09-25T10:25:14.327Z",
"dateUpdated": "2026-10-19T09:15:51.341Z",
"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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