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Fencer Vulns
high 7.8

CVE-2026-53365 json

vsock/virtio: fix zerocopy completion for multi-skb sends

published 2026-07-13 3 mo ago modified 2026-08-18 2 mo ago also EUVD-2026-43513

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 9%
public exploits
0
none known

Summary

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

vsock/virtio: fix zerocopy completion for multi-skb sends

When a large message is fragmented into multiple skbs, the zerocopy uarg is only allocated and attached to the last skb in the loop. Non-final skbs carry pinned user pages with no completion tracking, so the kernel has no way to notify userspace when those pages are safe to reuse. If the loop breaks early the uarg is never allocated at all, leaking pinned pages with no completion notification.

Fix this by following the approach used by TCP: allocate the zerocopy uarg (if not provided by the caller) before the send loop and attach it to every skb via skb_zcopy_set(), which takes a reference per skb. Each skb's completion properly decrements the refcount, and the notification only fires after the last skb is freed. On failure, if no data was sent, the uarg is cleanly aborted via net_zcopy_put_abort().

This issue was initially discovered by sashiko while reviewing commit 1cb36e252211 ("vsock/virtio: fix MSG_ZEROCOPY pinned-pages accounting") but was pre-existing.

Patch / fix

  • Linux Linux 6.12.97, 6.18.34, 7.0.11, 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-2026-53365

  • 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-2026-53365

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

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-2026-53365 updated cvss 7.8

kernel: vsock/virtio: fix zerocopy completion for multi-skb sends

  • 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, perf 5.14.0-687.56.1.el9_8, rtla 5.14.0-687.56.1.el9_8, python3-perf 5.14.0-687.56.1.el9_8, kernel-devel-matched 5.14.0-687.56.1.el9_8, kernel-64k-devel-matched 5.14.0-687.56.1.el9_8, +7 more
    fixed: vendor fix RHSA-2026:77689
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.64.1.el10_2, perf 6.12.0-211.64.1.el10_2, rtla 6.12.0-211.64.1.el10_2, python3-perf 6.12.0-211.64.1.el10_2, kernel-devel-matched 6.12.0-211.64.1.el10_2, kernel-64k-devel-matched 6.12.0-211.64.1.el10_2, +7 more
    fixed: vendor fix RHSA-2026:77690
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.56.1.el9_8, kernel-64k 5.14.0-687.56.1.el9_8, kernel-core 5.14.0-687.56.1.el9_8, kernel-tools 5.14.0-687.56.1.el9_8, kernel-modules 5.14.0-687.56.1.el9_8, kernel-64k-core 5.14.0-687.56.1.el9_8, +27 more
    fixed: vendor fix RHSA-2026:77689
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.64.1.el10_2, kernel-64k 6.12.0-211.64.1.el10_2, kernel-core 6.12.0-211.64.1.el10_2, kernel-tools 6.12.0-211.64.1.el10_2, kernel-modules 6.12.0-211.64.1.el10_2, kernel-64k-core 6.12.0-211.64.1.el10_2, +28 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, kernel-debuginfo-common-s390x 5.14.0-687.56.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.56.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.56.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.56.1.el9_8
    fixed: vendor fix RHSA-2026:77689
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.64.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.64.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.64.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.64.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.64.1.el10_2 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-64k 5.14.0-687.56.1.el9_8, kernel-rt-core 5.14.0-687.56.1.el9_8, kernel-rt-modules 5.14.0-687.56.1.el9_8, kernel-rt-64k-core 5.14.0-687.56.1.el9_8, kernel-rt-debug-core 5.14.0-687.56.1.el9_8, +14 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-64k 6.12.0-211.64.1.el10_2, kernel-rt-core 6.12.0-211.64.1.el10_2, kernel-rt-modules 6.12.0-211.64.1.el10_2, kernel-rt-64k-core 6.12.0-211.64.1.el10_2, kernel-rt-debug-core 6.12.0-211.64.1.el10_2, +14 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-core 5.14.0-687.56.1.el9_8, kernel-rt-modules 5.14.0-687.56.1.el9_8, kernel-rt-debug-core 5.14.0-687.56.1.el9_8, kernel-rt-modules-core 5.14.0-687.56.1.el9_8, kernel-rt-debug-modules 5.14.0-687.56.1.el9_8, +4 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-core 6.12.0-211.64.1.el10_2, kernel-rt-modules 6.12.0-211.64.1.el10_2, kernel-rt-debug-core 6.12.0-211.64.1.el10_2, kernel-rt-modules-core 6.12.0-211.64.1.el10_2, kernel-rt-debug-modules 6.12.0-211.64.1.el10_2, +4 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
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
2 mo ago

Exploit prediction

0.20% chance of exploitation in the next 30 days, higher than 9% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/MaherAzzouzi/vsockdrop referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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-404 Improper Resource Shutdown or Release
  • CWE-401 Missing Release of Memory after Effective Lifetime
Technology feeds

References

Sources

Fencer Vulns 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.