Skip to content
Fencer Intel
high 7.8

CVE-2026-63970 json

vsock/virtio: bind uarg before filling zerocopy skb

published 3mo ago modified 23d ago also EUVD-2026-45743

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 7%
public exploits
0
none known

Summary

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.

Patch / fix

  • Linux Linux 6.12.97, 6.18.35, 7.0.12, 7.1
  • linux Debian 13 6.12.100-1
  • linux Debian 14 7.0.12-1
  • linux-6.12 Debian 12 6.12.100-1~deb12u1

debian advisories DEBIAN-CVE-2026-63970

  • linux Ubuntu 24.04 LTS 6.8.0-147.147
  • linux Ubuntu 26.04 LTS 7.0.0-28.28
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1067.70
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1009.9
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1071.79
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1008.8
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1066.74
  • linux-gke Ubuntu 26.04 LTS 7.0.0-1003.4

ubuntu advisories UBUNTU-CVE-2026-63970

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel RHEL 10.2 6.12.0-211.64.1.el10_2
  • rv RHEL 10.2 6.12.0-211.64.1.el10_2
  • perf RHEL 10.2 6.12.0-211.64.1.el10_2
  • rtla RHEL 10.2 6.12.0-211.64.1.el10_2
  • libperf RHEL 10.2 6.12.0-211.64.1.el10_2
  • kernel-rt RHEL 10.2 6.12.0-211.64.1.el10_2
  • kernel-64k RHEL 10.2 6.12.0-211.64.1.el10_2
  • kernel-core RHEL 10.2 6.12.0-211.64.1.el10_2

red hat advisories RHSA-2026:77690RHSA-2026:77689

  • kernel-64kb SLE Module for Basesystem 15 SP7 6.4.0-150700.53.81.1
  • kernel-syms SLE Module for Development Tools 15 SP7 6.4.0-150700.53.81.1
  • kernel-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.53.81.1
  • kernel-source SLE Module for Development Tools 15 SP7, SLE Module for Basesystem 15 SP7 6.4.0-150700.53.81.1
  • kernel-default SLE Workstation Extension 15 SP7, SLE Module for Legacy 15 SP7, SLE Module for Basesystem 15 SP7 +2 more 6.4.0-150700.53.81.1
  • kernel-zfcpdump SLE Module for Basesystem 15 SP7 6.4.0-150700.53.81.1
  • kernel-obs-build SLE Module for Development Tools 15 SP7 6.4.0-150700.53.81.1
  • kernel-default-base SLE Module for Basesystem 15 SP7 6.4.0-150700.53.81.1.150700.17.45.1

suse advisories SUSE-SU-2026:4254-1SUSE-SU-2026:4369-1SUSE-SU-2026:23887-1SUSE-SU-2026:23902-1SUSE-SU-2026:23897-1SUSE-SU-2026:23881-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.38.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-azure openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.38.1

opensuse advisories openSUSE-SU-2026:21910-1

  • kernel AlmaLinux 9 5.14.0-687.56.1.el9_8
  • rv AlmaLinux 9 5.14.0-687.56.1.el9_8
  • perf AlmaLinux 9 5.14.0-687.56.1.el9_8
  • rtla AlmaLinux 9 5.14.0-687.56.1.el9_8
  • libperf AlmaLinux 9 5.14.0-687.56.1.el9_8
  • kernel-rt AlmaLinux 9 5.14.0-687.56.1.el9_8
  • kernel-64k AlmaLinux 9 5.14.0-687.56.1.el9_8
  • kernel-core AlmaLinux 9 5.14.0-687.56.1.el9_8

almalinux advisories ALSA-2026:77689ALSA-2026:77690

  • kernel Rocky Linux 10 6.12.0-211.64.1.el10_2
  • kernel Rocky Linux 9 5.14.0-687.56.1.el9_8

rocky linux advisories RLSA-2026:77690RLSA-2026:77689

Is CVE-2026-63970 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-63970 updated cvss 7.0

kernel: vsock/virtio: bind uarg before filling zerocopy skb

  • Red Hat Enterprise Linux kernel-modules-internal 6.12.0-211.64.1.el10_2
    fixed: vendor fix RHSA-2026:77690
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.56.1.el9_8, rv 5.14.0-741.20.1.el9_9, perf 5.14.0-687.56.1.el9_8, perf 5.14.0-741.20.1.el9_9, rtla 5.14.0-687.56.1.el9_8, rtla 5.14.0-741.20.1.el9_9, +20 more
    fixed: vendor fix RHSA-2026:77689
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.64.1.el10_2, rv 6.12.0-264.14.1.el10_3, perf 6.12.0-211.64.1.el10_2, perf 6.12.0-264.14.1.el10_3, rtla 6.12.0-211.64.1.el10_2, rtla 6.12.0-264.14.1.el10_3, +20 more
    fixed: vendor fix RHSA-2026:77690
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.56.1.el9_8, kernel 5.14.0-741.20.1.el9_9, kernel-64k 5.14.0-687.56.1.el9_8, kernel-64k 5.14.0-741.20.1.el9_9, kernel-core 5.14.0-687.56.1.el9_8, kernel-core 5.14.0-741.20.1.el9_9, +60 more
    fixed: vendor fix RHSA-2026:77689
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.64.1.el10_2, kernel 6.12.0-264.14.1.el10_3, kernel-64k 6.12.0-211.64.1.el10_2, kernel-64k 6.12.0-264.14.1.el10_3, kernel-core 6.12.0-211.64.1.el10_2, kernel-core 6.12.0-264.14.1.el10_3, +62 more
    fixed: vendor fix RHSA-2026:77690
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.56.1.el9_8, libperf 5.14.0-741.20.1.el9_9, kernel-debuginfo-common-s390x 5.14.0-687.56.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-741.20.1.el9_9, kernel-debuginfo-common-x86_64 5.14.0-687.56.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-741.20.1.el9_9, +4 more
    fixed: vendor fix RHSA-2026:77689
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.64.1.el10_2, libperf 6.12.0-264.14.1.el10_3, kernel-debuginfo-common-s390x 6.12.0-211.64.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-264.14.1.el10_3, kernel-debuginfo-common-x86_64 6.12.0-211.64.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-264.14.1.el10_3, +4 more Red Hat Enterprise Linux Hidden (v. 10) kernel-modules-internal 6.12.0-211.64.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.64.1.el10_2
    fixed: vendor fix RHSA-2026:77690
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.56.1.el9_8, kernel-rt 5.14.0-741.20.1.el9_9, kernel-rt-64k 5.14.0-687.56.1.el9_8, kernel-rt-64k 5.14.0-741.20.1.el9_9, kernel-rt-core 5.14.0-687.56.1.el9_8, kernel-rt-core 5.14.0-741.20.1.el9_9, +34 more
    fixed: vendor fix RHSA-2026:77689
show 4 more
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.64.1.el10_2, kernel-rt 6.12.0-264.14.1.el10_3, kernel-rt-64k 6.12.0-211.64.1.el10_2, kernel-rt-64k 6.12.0-264.14.1.el10_3, kernel-rt-core 6.12.0-211.64.1.el10_2, kernel-rt-core 6.12.0-264.14.1.el10_3, +34 more
    fixed: vendor fix RHSA-2026:77690
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.56.1.el9_8, kernel-rt 5.14.0-741.20.1.el9_9, kernel-rt-core 5.14.0-687.56.1.el9_8, kernel-rt-core 5.14.0-741.20.1.el9_9, kernel-rt-modules 5.14.0-687.56.1.el9_8, kernel-rt-modules 5.14.0-741.20.1.el9_9, +15 more
    fixed: vendor fix RHSA-2026:77689
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.64.1.el10_2, kernel-rt 6.12.0-264.14.1.el10_3, kernel-rt-core 6.12.0-211.64.1.el10_2, kernel-rt-core 6.12.0-264.14.1.el10_3, kernel-rt-modules 6.12.0-211.64.1.el10_2, kernel-rt-modules 6.12.0-264.14.1.el10_3, +15 more
    fixed: vendor fix RHSA-2026:77690
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
26d ago

Exploit prediction

0.18% chance of exploitation in the next 30 days, higher than 7% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Weakness
  • CWE-401 Missing Release of Memory after Effective Lifetime
  • CWE-416 Use After Free
Technology feeds

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.