Description
In the Linux kernel, the following vulnerability has been resolved:

bpf: Reject untrusted allocated-object pointers

When the final RCU read-side critical section ends, a local kptr is demoted
to PTR_UNTRUSTED but retains MEM_ALLOC. The pointer may be NULL or may refer
to an object whose lifetime is no longer protected.

type_is_ptr_alloc_obj() nevertheless recognizes any PTR_TO_BTF_ID with
MEM_ALLOC as a live allocated object. In particular, a refcount-only local
kptr never carries NON_OWN_REF, so it still passes the
bpf_refcount_acquire() argument check after RCU protection ends. The kfunc
can then dereference NULL or stale memory.

Make type_is_ptr_alloc_obj() reject PTR_UNTRUSTED pointers. Since
type_is_non_owning_ref() is based on the same predicate, graph kfunc
arguments obey the same live-object requirement. Fault-protected reads of
the demoted pointer remain valid: writes are already rejected, and read
fixups use bpf_may_fault_on_deref() rather than this predicate.

[ kkd: Rewrote commit log ]
Published: 2026-09-25
Score: 7.0 High
EPSS: < 1% Very Low
KEV: No
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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
Debian DSA Debian DSA DSA-6528-1 linux security update
History

Tue, 29 Sep 2026 22:00:00 +0000

Type Values Removed Values Added
Weaknesses CWE-416
CWE-476

Tue, 29 Sep 2026 13:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-825
References
Metrics threat_severity

None

cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

threat_severity

Moderate


Fri, 25 Sep 2026 15:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-416
CWE-476

Fri, 25 Sep 2026 10:30:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: bpf: Reject untrusted allocated-object pointers When the final RCU read-side critical section ends, a local kptr is demoted to PTR_UNTRUSTED but retains MEM_ALLOC. The pointer may be NULL or may refer to an object whose lifetime is no longer protected. type_is_ptr_alloc_obj() nevertheless recognizes any PTR_TO_BTF_ID with MEM_ALLOC as a live allocated object. In particular, a refcount-only local kptr never carries NON_OWN_REF, so it still passes the bpf_refcount_acquire() argument check after RCU protection ends. The kfunc can then dereference NULL or stale memory. Make type_is_ptr_alloc_obj() reject PTR_UNTRUSTED pointers. Since type_is_non_owning_ref() is based on the same predicate, graph kfunc arguments obey the same live-object requirement. Fault-protected reads of the demoted pointer remain valid: writes are already rejected, and read fixups use bpf_may_fault_on_deref() rather than this predicate. [ kkd: Rewrote commit log ]
Title bpf: Reject untrusted allocated-object pointers
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-09-25T10:23:51.126Z

Reserved: 2026-09-25T10:19:56.071Z

Link: CVE-2026-98037

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-25T11:17:32.443

Modified: 2026-09-25T11:17:32.443

Link: CVE-2026-98037

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-09-25T00:00:00Z

Links: CVE-2026-98037 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-09-29T21:45:17Z

Weaknesses