CVE-2026-98036 (GCVE-0-2026-98036)
Vulnerability from cvelistv5
Published
2026-09-25 10:23
Modified
2026-10-19 09:12
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
bpf: Preserve special fields in recycled rhtab elements
rhtab_map_update_elem() initializes special fields after obtaining an
element from bpf_mem_cache_alloc(). The allocator can return a fresh,
zeroed unit, or recycle one from its RCU-pending lists before the
registered destructor has run.
A BPF program can retain a map-value pointer after deleting its element
and initialize and arm a timer through that pointer. If the deleted unit
is recycled, check_and_init_map_value() clears the only pointer to the
timer. Neither a later deletion nor rhtab_mem_dtor() can then cancel it,
and the callback can run with its key and value pointing into freed memory.
Do not reinitialize special fields on insertion. Fresh allocator units are
already zeroed. For recycled units, the special fields are ownership state
that must remain visible to the eventual destructor. copy_map_value()
already skips those fields, matching the non-preallocated hash-map path and
the lifecycle established by commit 275c30bcee66 ("bpf: Don't reinit map
value in prealloc_lru_pop").
[ kkd: Split out the fix and rewrote the commit log ]
References
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"kernel/bpf/hashtab.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "6a5266b8288216b86602ff687d528abfb066dfd8",
"status": "affected",
"version": "6905f8601298ecd2d1932a4b4849bf265201118e",
"versionType": "git"
},
{
"lessThan": "5df46ddcb7b36878c1b691e9057a0509042a2567",
"status": "affected",
"version": "6905f8601298ecd2d1932a4b4849bf265201118e",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"kernel/bpf/hashtab.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "7.2"
},
{
"lessThan": "7.2",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"version": "7.2.7",
"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": "7.2.7",
"versionStartIncluding": "7.2",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.3",
"versionStartIncluding": "7.2",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Preserve special fields in recycled rhtab elements\n\nrhtab_map_update_elem() initializes special fields after obtaining an\nelement from bpf_mem_cache_alloc(). The allocator can return a fresh,\nzeroed unit, or recycle one from its RCU-pending lists before the\nregistered destructor has run.\n\nA BPF program can retain a map-value pointer after deleting its element\nand initialize and arm a timer through that pointer. If the deleted unit\nis recycled, check_and_init_map_value() clears the only pointer to the\ntimer. Neither a later deletion nor rhtab_mem_dtor() can then cancel it,\nand the callback can run with its key and value pointing into freed memory.\n\nDo not reinitialize special fields on insertion. Fresh allocator units are\nalready zeroed. For recycled units, the special fields are ownership state\nthat must remain visible to the eventual destructor. copy_map_value()\nalready skips those fields, matching the non-preallocated hash-map path and\nthe lifecycle established by commit 275c30bcee66 (\"bpf: Don\u0027t reinit map\nvalue in prealloc_lru_pop\").\n\n[ kkd: Split out the fix and rewrote the commit log ]"
}
],
"providerMetadata": {
"dateUpdated": "2026-10-19T09:12:41.963Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/6a5266b8288216b86602ff687d528abfb066dfd8"
},
{
"url": "https://git.kernel.org/stable/c/5df46ddcb7b36878c1b691e9057a0509042a2567"
}
],
"title": "bpf: Preserve special fields in recycled rhtab elements",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-98036",
"datePublished": "2026-09-25T10:23:50.530Z",
"dateReserved": "2026-09-25T10:19:56.071Z",
"dateUpdated": "2026-10-19T09:12:41.963Z",
"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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