Bug 2536525 (CVE-2026-93044)

Summary:	CVE-2026-93044 kernel: bpf: Disallow interpreter fallback for arena-related insns
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
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) component. This vulnerability occurs when the BPF interpreter attempts to process specific arena-related instructions that it does not support, particularly when a BPF program uses an arena map. This can lead to a kernel bug and an 'Oops' condition, resulting in a system crash and a Denial of Service (DoS) for the affected system.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-09-17 18:18:01 UTC

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

bpf: Disallow interpreter fallback for arena-related insns

Since the interpreter does not support the arena-related insns,
interpreter fallback should not be allowed for these insns in
core.c::__bpf_prog_select_runtime().

Currently, when the interpreter executes the arena ST/LDX/STX insns,
it would hit the BUG_ON() in ___bpf_prog_run() at run time.

[    2.579196] BPF interpreter: unknown opcode a2 (imm: 0x0)
[    2.579998] ------------[ cut here ]------------
[    2.580652] kernel BUG at kernel/bpf/core.c:2349!
[    2.581314] Oops: invalid opcode: 0000 [#1] SMP PTI

Set jit_required as true when arena map is used in the prog to disallow
interpreter fallback for arena-related insns.

Comment 1 gkamathe 2026-09-19 19:26:08 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-93044.mbox