Bug 2418848 (CVE-2025-40236)

Summary: CVE-2025-40236 kernel: virtio-net: zero unused hash fields
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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OS: Linux   
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Description OSIDB Bzimport 2025-12-04 16:04:12 UTC 
In the Linux kernel, the following vulnerability has been resolved:

virtio-net: zero unused hash fields

When GSO tunnel is negotiated virtio_net_hdr_tnl_from_skb() tries to
initialize the tunnel metadata but forget to zero unused rxhash
fields. This may leak information to another side. Fixing this by
zeroing the unused hash fields.
Comment 1 Alexander B 2025-12-05 14:46:11 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025120402-CVE-2025-40236-617c@gregkh/T