Bug 2554973 (CVE-2026-98572)

Summary:	CVE-2026-98572 kernel: bpf: Fix immediate JMP JEQ/JNE on MIPS32
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 extended Berkeley Packet Filter (eBPF) Just-In-Time (JIT) compiler on 32-bit MIPS systems. An instruction generation error during 64-bit jump comparisons causes negative numeric constants to be incorrectly evaluated against a hardware register instead of the intended values. A local user capable of loading BPF programs can exploit this issue to produce invalid comparison results, potentially bypassing security filters or causing unexpected program execution paths.	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 2026-10-18 15:36:44 UTC

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

bpf: Fix immediate JMP JEQ/JNE on MIPS32

An addu instruction was emitted instead of addiu, causing the immediate
value 1 to be interpreted as register $at. This made the comparison
result invalid when the immediate operand was negative. Note that $at
is mapped to BPF_REG_AX, which is used for constant blinding.

Fix the instruction to use the immediate form.

Found with test_bpf on MIPS32r1 emulated by QEMU.