Bug 2502411 (CVE-2026-63970) - CVE-2026-63970 kernel: vsock/virtio: bind uarg before filling zerocopy skb
Summary: CVE-2026-63970 kernel: vsock/virtio: bind uarg before filling zerocopy skb
Keywords:
Status: NEW
Alias: CVE-2026-63970
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-07-19 16:06 UTC by OSIDB Bzimport
Modified: 2026-10-08 10:51 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2026:77689 0 None None None 2026-10-08 10:51:53 UTC
Red Hat Product Errata RHSA-2026:77690 0 None None None 2026-10-08 09:52:23 UTC

Description OSIDB Bzimport 2026-07-19 16:06:42 UTC
In the Linux kernel, the following vulnerability has been resolved:

vsock/virtio: bind uarg before filling zerocopy skb

virtio_transport_send_pkt_info() allocates or reuses the zerocopy uarg
before entering the send loop, but virtio_transport_alloc_skb() still
fills the skb before it inherits that uarg. When fixed-buffer vectored
zerocopy hits MAX_SKB_FRAGS, io_sg_from_iter() may partially attach
managed frags and return -EMSGSIZE. The rollback path call kfree_skb()
to free an skb that carries SKBFL_MANAGED_FRAG_REFS but no uarg, so
skb_release_data() falls through to ordinary frag unref.

Pass the uarg into virtio_transport_alloc_skb() and bind it immediately
before virtio_transport_fill_skb(). This keeps control or no-payload skbs
untouched while ensuring success and rollback share one lifetime rule.

Comment 5 Jon Orris 2026-10-08 09:52:22 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:77690 https://access.redhat.com/errata/RHSA-2026:77690

Comment 6 Jon Orris 2026-10-08 10:51:52 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:77689 https://access.redhat.com/errata/RHSA-2026:77689


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