CVE-2026-43292 (GCVE-0-2026-43292)
Vulnerability from cvelistv5
Published
2026-05-08 13:11
Modified
2026-05-11 22:21
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
mm/vmalloc: prevent RCU stalls in kasan_release_vmalloc_node
When CONFIG_PAGE_OWNER is enabled, freeing KASAN shadow pages during
vmalloc cleanup triggers expensive stack unwinding that acquires RCU read
locks. Processing a large purge_list without rescheduling can cause the
task to hold CPU for extended periods (10+ seconds), leading to RCU stalls
and potential OOM conditions.
The issue manifests in purge_vmap_node() -> kasan_release_vmalloc_node()
where iterating through hundreds or thousands of vmap_area entries and
freeing their associated shadow pages causes:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6229/1:b..l
...
task:kworker/0:17 state:R running task stack:28840 pid:6229
...
kasan_release_vmalloc_node+0x1ba/0xad0 mm/vmalloc.c:2299
purge_vmap_node+0x1ba/0xad0 mm/vmalloc.c:2299
Each call to kasan_release_vmalloc() can free many pages, and with
page_owner tracking, each free triggers save_stack() which performs stack
unwinding under RCU read lock. Without yielding, this creates an
unbounded RCU critical section.
Add periodic cond_resched() calls within the loop to allow:
- RCU grace periods to complete
- Other tasks to run
- Scheduler to preempt when needed
The fix uses need_resched() for immediate response under load, with a
batch count of 32 as a guaranteed upper bound to prevent worst-case stalls
even under light load.
References
| URL | Tags | |
|---|---|---|
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"mm/vmalloc.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
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"versionType": "git"
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{
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"versions": [
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{
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"version": "0",
"versionType": "semver"
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{
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"status": "unaffected",
"version": "6.12.75",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "6.18.16",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "6.19.6",
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{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix"
}
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}
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"cpeApplicability": [
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"nodes": [
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"versionStartIncluding": "6.9",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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}
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"negate": false,
"operator": "OR"
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],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/vmalloc: prevent RCU stalls in kasan_release_vmalloc_node\n\nWhen CONFIG_PAGE_OWNER is enabled, freeing KASAN shadow pages during\nvmalloc cleanup triggers expensive stack unwinding that acquires RCU read\nlocks. Processing a large purge_list without rescheduling can cause the\ntask to hold CPU for extended periods (10+ seconds), leading to RCU stalls\nand potential OOM conditions.\n\nThe issue manifests in purge_vmap_node() -\u003e kasan_release_vmalloc_node()\nwhere iterating through hundreds or thousands of vmap_area entries and\nfreeing their associated shadow pages causes:\n\n rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:\n rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6229/1:b..l\n ...\n task:kworker/0:17 state:R running task stack:28840 pid:6229\n ...\n kasan_release_vmalloc_node+0x1ba/0xad0 mm/vmalloc.c:2299\n purge_vmap_node+0x1ba/0xad0 mm/vmalloc.c:2299\n\nEach call to kasan_release_vmalloc() can free many pages, and with\npage_owner tracking, each free triggers save_stack() which performs stack\nunwinding under RCU read lock. Without yielding, this creates an\nunbounded RCU critical section.\n\nAdd periodic cond_resched() calls within the loop to allow:\n- RCU grace periods to complete\n- Other tasks to run\n- Scheduler to preempt when needed\n\nThe fix uses need_resched() for immediate response under load, with a\nbatch count of 32 as a guaranteed upper bound to prevent worst-case stalls\neven under light load."
}
],
"providerMetadata": {
"dateUpdated": "2026-05-11T22:21:44.094Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
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"url": "https://git.kernel.org/stable/c/2efa9c02c9b4c0d6866aa445f11056809b25ca28"
},
{
"url": "https://git.kernel.org/stable/c/1afe45f89d54b7183768ebbbbf14238ec187ab5c"
},
{
"url": "https://git.kernel.org/stable/c/b351fbe71091f7c8676c8ba597653d08b6719447"
},
{
"url": "https://git.kernel.org/stable/c/5747435e0fd474c24530ef1a6822f47e7d264b27"
}
],
"title": "mm/vmalloc: prevent RCU stalls in kasan_release_vmalloc_node",
"x_generator": {
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}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-43292",
"datePublished": "2026-05-08T13:11:16.017Z",
"dateReserved": "2026-05-01T14:12:55.999Z",
"dateUpdated": "2026-05-11T22:21:44.094Z",
"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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