CVE-2026-31526 (GCVE-0-2026-31526)
Vulnerability from cvelistv5
Published
2026-04-22 13:54
Modified
2026-10-21 12:39
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix exception exit lock checking for subprogs
process_bpf_exit_full() passes check_lock = !curframe to
check_resource_leak(), which is false in cases when bpf_throw() is
called from a static subprog. This makes check_resource_leak() to skip
validation of active_rcu_locks, active_preempt_locks, and
active_irq_id on exception exits from subprogs.
At runtime bpf_throw() unwinds the stack via ORC without releasing any
user-acquired locks, which may cause various issues as the result.
Fix by setting check_lock = true for exception exits regardless of
curframe, since exceptions bypass all intermediate frame
cleanup. Update the error message prefix to "bpf_throw" for exception
exits to distinguish them from normal BPF_EXIT.
Fix reject_subprog_with_rcu_read_lock test which was previously
passing for the wrong reason. Test program returned directly from the
subprog call without closing the RCU section, so the error was
triggered by the unclosed RCU lock on normal exit, not by
bpf_throw. Update __msg annotations for affected tests to match the
new "bpf_throw" error prefix.
The spin_lock case is not affected because they are already checked [1]
at the call site in do_check_insn() before bpf_throw can run.
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/kernel/bpf/verifier.c?h=v7.0-rc4#n21098
References
| URL | Tags | |
|---|---|---|
Impacted products
{
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"affected": [
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"product": "Linux",
"programFiles": [
"kernel/bpf/verifier.c",
"tools/testing/selftests/bpf/progs/exceptions_fail.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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{
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},
{
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"versionType": "git"
},
{
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},
{
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"vendor": "Linux",
"versions": [
{
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"version": "6.7"
},
{
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"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "6.12.114",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "6.18.21",
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},
{
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"status": "unaffected",
"version": "6.19.11",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.0",
"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": "6.12.114",
"versionStartIncluding": "6.7",
"vulnerable": true
},
{
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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\nbpf: Fix exception exit lock checking for subprogs\n\nprocess_bpf_exit_full() passes check_lock = !curframe to\ncheck_resource_leak(), which is false in cases when bpf_throw() is\ncalled from a static subprog. This makes check_resource_leak() to skip\nvalidation of active_rcu_locks, active_preempt_locks, and\nactive_irq_id on exception exits from subprogs.\n\nAt runtime bpf_throw() unwinds the stack via ORC without releasing any\nuser-acquired locks, which may cause various issues as the result.\n\nFix by setting check_lock = true for exception exits regardless of\ncurframe, since exceptions bypass all intermediate frame\ncleanup. Update the error message prefix to \"bpf_throw\" for exception\nexits to distinguish them from normal BPF_EXIT.\n\nFix reject_subprog_with_rcu_read_lock test which was previously\npassing for the wrong reason. Test program returned directly from the\nsubprog call without closing the RCU section, so the error was\ntriggered by the unclosed RCU lock on normal exit, not by\nbpf_throw. Update __msg annotations for affected tests to match the\nnew \"bpf_throw\" error prefix.\n\nThe spin_lock case is not affected because they are already checked [1]\nat the call site in do_check_insn() before bpf_throw can run.\n\n[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/kernel/bpf/verifier.c?h=v7.0-rc4#n21098"
}
],
"providerMetadata": {
"dateUpdated": "2026-10-21T12:39:24.405Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
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"references": [
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"url": "https://git.kernel.org/stable/c/4eca06a55417c3b2e538656d12c89e224343653e"
},
{
"url": "https://git.kernel.org/stable/c/c0281da1f2aa5c2fca3a05f79b86bea96591c358"
},
{
"url": "https://git.kernel.org/stable/c/5a399f3117642494e35545f6ca397d3e177c1f9b"
},
{
"url": "https://git.kernel.org/stable/c/6c2128505f61b504c79a20b89596feba61388112"
}
],
"title": "bpf: Fix exception exit lock checking for subprogs",
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"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-31526",
"datePublished": "2026-04-22T13:54:39.800Z",
"dateReserved": "2026-03-09T15:48:24.111Z",
"dateUpdated": "2026-10-21T12:39:24.405Z",
"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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