Bug 2554954 (CVE-2026-98611)

Summary:	CVE-2026-98611 kernel: bpf: Check params size before reading reserved fields
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 BPF (Berkeley Packet Filter) subsystem. The bpf_crypto_ctx_create() function attempts to read reserved fields from a parameter structure prior to verifying that the supplied buffer is sufficiently large. A local user capable of loading BPF programs can exploit this issue by supplying an undersized buffer, causing an out-of-bounds read from kernel memory. This flaw could lead to the exposure of sensitive kernel information or trigger a system crash resulting in a Denial of Service (DoS).	Story Points:	---
Clone Of:		Environment:
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Regression:	---	Mount Type:	---
Documentation:	---	CRM:
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-10-18 15:35:26 UTC

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

bpf: Check params size before reading reserved fields

bpf_crypto_ctx_create() is a kfunc whose second argument is declared
with the __sz annotation, so the verifier only guarantees that
params__sz bytes of params are valid.  The function nevertheless reads
params->reserved[0] and params->reserved[1] (offsets 14 and 15) before
comparing params__sz against the size of struct bpf_crypto_params, so a
BPF program can pass a shorter buffer and have the kernel read past the
region that was validated for it.

Move the size check in front of the reserved field reads.

Comment 1 Mauro Matteo Cascella 2026-10-21 07:26:37 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98611.mbox