Use-after-free in Linux kernel - CVE-2026-63919

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Main Vulnerability Database Vulnerabilities #VU138724

Use-after-free in Linux kernel - CVE-2026-63919

Published: July 20, 2026


Vulnerability identifier: #VU138724
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-63919
CWE-ID: CWE-416
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to a use-after-free in xfrm transport-mode deferred reinjection handling in net/xfrm/xfrm_input.c when processing deferred transport reinjection callbacks that use a stored network namespace pointer. A local user can trigger deferred transport reinjection with a dangling net namespace reference to cause a denial of service.


Affected software

Linux kernel
Red Hat Enterprise Linux for Real Time
Red Hat Enterprise Linux for Real Time for NFV
Red Hat Enterprise Linux Server - AUS
Red Hat Enterprise Linux Server - TUS
Red Hat Enterprise Linux for ARM 64 - Extended Update Support
Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
Red Hat Enterprise Linux for x86_64 - Extended Update Support
Red Hat CodeReady Linux Builder for IBM z Systems - Extended Update Support
Red Hat CodeReady Linux Builder for Power, little endian - Extended Update Support
Red Hat CodeReady Linux Builder for x86_64 - Extended Update Support
Red Hat CodeReady Linux Builder for ARM 64 - Extended Update Support
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for x86_64
Ubuntu
openEuler
Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions
kernel (Red Hat package)
kernel-rt (Red Hat package)
python3-perf
python3-perf-debuginfo
perf-debuginfo
perf
kernel-tools-devel
kernel-tools-debuginfo
kernel-tools
kernel-source
kernel-headers
kernel-devel
kernel-debugsource
kernel-debuginfo
bpftool-debuginfo
bpftool
kernel
kernel-extra-modules
linux (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-oracle-5.15 (Ubuntu package)
linux-gcp-5.15 (Ubuntu package)
linux-gcp (Ubuntu package)
linux-gke (Ubuntu package)
linux-nvidia-tegra (Ubuntu package)
linux-azure (Ubuntu package)
linux-ibm (Ubuntu package)
linux-aws (Ubuntu package)
linux-oracle-7.0 (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-azure-7.0 (Ubuntu package)
linux-nvidia-bos (Ubuntu package)

How to mitigate CVE-2026-63919

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
kernel (Red Hat package) - addressed in versions 4.18.0-305.211.1.el8_4, 4.18.0-372.220.1.el8_6, 4.18.0-477.172.1.el8_8, 5.14.0-427.154.1.el9_4, 5.14.0-570.146.1.el9_6, 6.12.0-55.108.1.el10_0, 6.12.0-211.55.1.el10_2
kernel-rt (Red Hat package) - addressed in versions 4.18.0-553.164.1.rt7.505.el8_10, 5.14.0-284.197.1.rt14.482.el9_2
python3-perf - update to 6.6.0-145.3.29.160
python3-perf-debuginfo - update to 6.6.0-145.3.29.160
perf-debuginfo - update to 6.6.0-145.3.29.160
perf - update to 6.6.0-145.3.29.160
kernel-tools-devel - update to 6.6.0-145.3.29.160
kernel-tools-debuginfo - update to 6.6.0-145.3.29.160
kernel-tools - update to 6.6.0-145.3.29.160
kernel-source - update to 6.6.0-145.3.29.160
kernel-headers - update to 6.6.0-145.3.29.160
kernel-devel - update to 6.6.0-145.3.29.160
kernel-debugsource - update to 6.6.0-145.3.29.160
kernel-debuginfo - update to 6.6.0-145.3.29.160
bpftool-debuginfo - update to 6.6.0-145.3.29.160
bpftool - update to 6.6.0-145.3.29.160
kernel - update to 6.6.0-145.3.29.160
kernel-extra-modules - update to 6.6.0-145.3.29.160
linux (Ubuntu package) - addressed in versions 5.15.0-195.205~20.04.1, 5.15.0-195.205, 5.15.0-198.208~20.04.1, 5.15.0-198.208+fips1, 5.15.0-1080.84, 5.15.0-1100.108, 5.15.0-1109.111, 5.15.0-1109.114, 5.15.0-1111.115~20.04.1, 5.15.0-1111.115, 5.15.0-1112.118~20.04.1, 5.15.0-1112.118, 5.15.0-1113.119, 5.15.0-1114.120, 5.15.0-1116.125~20.04.1, 5.15.0-1117.124~20.04.1, 5.15.0-1117.124, 5.15.0-1117.124+fips1, 5.15.0-1122.131~20.04.1, 5.15.0-1123.132~20.04.1, 5.15.0-1123.132, 5.15.0-1123.132+fips1, 5.15.0.195.160, 5.15.0.195.205~20.04.1, 5.15.0.198.114, 5.15.0.198.171, 5.15.0.198.208~20.04.1, 5.15.0.1080.83~20.04.1, 5.15.0.1100.99, 5.15.0.1109.105, 5.15.0.1109.113, 5.15.0.1111.108, 5.15.0.1111.115~20.04.1, 5.15.0.1112.111, 5.15.0.1112.118~20.04.1, 5.15.0.1113.112, 5.15.0.1114.110, 5.15.0.1116.120, 5.15.0.1117.113, 5.15.0.1117.120, 5.15.0.1117.124~20.04.1, 5.15.0.1122.131~20.04.1, 5.15.0.1123.107, 5.15.0.1123.121, 5.15.0.1123.132~20.04.1
linux-nvidia (Ubuntu package) - addressed in versions 5.15.0-1112.113, 5.15.0.1112.112, 7.0.0-1016.16~24.04.1, 7.0.0-1016.16
linux-oracle-5.15 (Ubuntu package) - addressed in versions 5.15.0-1114.120~20.04.1, 5.15.0.1114.120~20.04.1
linux-gcp-5.15 (Ubuntu package) - addressed in versions 5.15.0-1118.128~20.04.1, 5.15.0.1118.128~20.04.1
linux-gcp (Ubuntu package) - addressed in versions 5.15.0-1118.128, 5.15.0-1118.128+fips1, 5.15.0.1118.107, 5.15.0.1118.115, 6.8.0-1070.78
linux-gke (Ubuntu package) - addressed in versions 6.8.0-146.146.1~22.04.1, 6.8.0-146.146.1, 6.8.0-1051.55, 6.8.0-1063.66, 6.8.0-1064.67~22.04.1, 6.8.0-1064.67, 6.8.0-1064.67.1, 6.8.0-1065.73, 6.8.0-1066.67
linux-nvidia-tegra (Ubuntu package) - update to 6.8.0-1035.38
linux-azure (Ubuntu package) - addressed in versions 6.8.0-1068.75~22.04.1, 6.8.0-1068.75, 6.8.0-1069.77+fips1, 6.8.0-1070.78~22.04.1, 6.8.0-1070.78, 7.0.0-1009.9, 7.0.0-1010.10
linux-ibm (Ubuntu package) - addressed in versions 7.0.0-1008.8, 7.0.0-1010.10
linux-aws (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1015.15
linux-oracle-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-gcp-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-azure-7.0 (Ubuntu package) - update to 7.0.0-1014.14~24.04.1
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2016.16

External References

Related Security Bulletins