Bug 2541291 (CVE-2026-98062)

Summary:	CVE-2026-98062 kernel: bpf: Mark signal tracepoint siginfo arguments as scalar
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the Linux kernel's Berkeley Packet Filter (BPF) subsystem. The kernel incorrectly treats certain signal tracepoint arguments as trusted memory pointers, even when special non-pointer indicator values are passed during signal delivery. A local user with privileges to attach BPF programs can exploit this issue to dereference invalid memory addresses, causing a kernel crash and resulting in a Denial of Service (DoS).	Story Points:	---
Clone Of:		Environment:
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Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-09-25 11:15:30 UTC

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

bpf: Mark signal tracepoint siginfo arguments as scalar

The signal_generate and signal_deliver tracepoints declare their info
argument as a struct kernel_siginfo pointer. btf_ctx_access() therefore
treats it as a trusted pointer for tp_btf programs.

Signal delivery also uses SEND_SIG_NOINFO and SEND_SIG_PRIV as special
values for this argument. Those values are zero and one respectively,
and are not pointers. A tp_btf program can currently dereference either
value and fault the kernel. In particular, signal_generate can run from
timer interrupt context, turning the fault into a kernel panic.

Record both tracepoints in raw_tp_null_args[] and mark argument one as
a non-pointer. This preserves scalar access to the cookie while rejecting
direct and helper-mediated pointer use. Merely marking it nullable would
not suffice because SEND_SIG_PRIV is nonzero.

Comment 1 Keith Grant 2026-09-29 00:18:04 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98062.mbox