Observable discrepancy in Linux kernel - CVE-2026-43261

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Main Vulnerability Database Vulnerabilities #VU130436

Observable discrepancy in Linux kernel - CVE-2026-43261

Published: May 7, 2026


Vulnerability identifier: #VU130436
CSH Severity: Low
CVSS v4: 2 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-43261
CWE-ID: CWE-203
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local attacker to disclose sensitive information.

The vulnerability exists due to observable timing discrepancy in branch prediction on TSV110 arm64 processors when executing code that influences branch history. A local attacker can perform a Spectre-BHB side-channel attack to disclose sensitive information.

The issue is specific to TSV110 processors.


Affected software

Linux kernel
Ubuntu
openEuler
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
python3-perf
python3-perf-debuginfo
linux (Ubuntu package)
linux-aws (Ubuntu package)
linux-nvidia-tegra (Ubuntu package)
linux-nvidia-tegra-5.15 (Ubuntu package)
linux-intel-iot-realtime (Ubuntu package)
linux-ibm-5.15 (Ubuntu package)
linux-intel-iotg (Ubuntu package)
linux-azure (Ubuntu package)
linux-azure-5.15 (Ubuntu package)
linux-gcp-5.15 (Ubuntu package)
linux-azure-fips (Ubuntu package)
linux-azure-fde (Ubuntu package)
linux-hwe-6.8 (Ubuntu package)
linux-aws-6.8 (Ubuntu package)
linux-raspi (Ubuntu package)
linux-azure-fde-6.8 (Ubuntu package)
linux-raspi-realtime (Ubuntu package)

How to mitigate CVE-2026-43261

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
perf-debuginfo - addressed in versions 5.10.0-315.0.0.218, 6.6.0-145.0.13.139, 6.6.0-145.1.12.150
perf - addressed in versions 5.10.0-315.0.0.218, 6.6.0-145.0.13.139, 6.6.0-145.1.12.150
kernel-tools-devel - addressed in versions 5.10.0-315.0.0.218, 6.6.0-145.0.13.139, 6.6.0-145.1.12.150
kernel-tools-debuginfo - addressed in versions 5.10.0-315.0.0.218, 6.6.0-145.0.13.139, 6.6.0-145.1.12.150
kernel-tools - addressed in versions 5.10.0-315.0.0.218, 6.6.0-145.0.13.139, 6.6.0-145.1.12.150
kernel-source - addressed in versions 5.10.0-315.0.0.218, 6.6.0-145.0.13.139, 6.6.0-145.1.12.150
kernel-headers - addressed in versions 5.10.0-315.0.0.218, 6.6.0-145.0.13.139, 6.6.0-145.1.12.150
kernel-devel - addressed in versions 5.10.0-315.0.0.218, 6.6.0-145.0.13.139, 6.6.0-145.1.12.150
kernel-debugsource - addressed in versions 5.10.0-315.0.0.218, 6.6.0-145.0.13.139, 6.6.0-145.1.12.150
kernel-debuginfo - addressed in versions 5.10.0-315.0.0.218, 6.6.0-145.0.13.139, 6.6.0-145.1.12.150
bpftool-debuginfo - addressed in versions 5.10.0-315.0.0.218, 6.6.0-145.0.13.139, 6.6.0-145.1.12.150
bpftool - addressed in versions 5.10.0-315.0.0.218, 6.6.0-145.0.13.139, 6.6.0-145.1.12.150
kernel - addressed in versions 5.10.0-315.0.0.218, 6.6.0-145.0.13.139, 6.6.0-145.1.12.150
python3-perf - addressed in versions 5.10.0-315.0.0.218, 6.6.0-145.0.13.139, 6.6.0-145.1.12.150
python3-perf-debuginfo - addressed in versions 5.10.0-315.0.0.218, 6.6.0-145.0.13.139, 6.6.0-145.1.12.150
linux (Ubuntu package) - addressed in versions 5.15.0.184.155, 5.15.0-184.194, 5.15.0-184.194~20.04.1, 5.15.0.186.166, 5.15.0-186.196, 5.15.0-186.196~20.04.1, 5.15.0.1075.78, 5.15.0-1075.79, 5.15.0.1095.94, 5.15.0-1095.103, 5.15.0.1104.100, 5.15.0-1104.109, 5.15.0.1108.107, 5.15.0-1108.114, 5.15.0.1111.115, 5.15.0-1111.120+fips1, 5.15.0.1112.102, 5.15.0.1112.109, 5.15.0-1112.122, 5.15.0-1112.122+fips1, 6.8.0-134.134, 6.8.0-1057.58~22.04.1, 6.8.0-1058.61+fips1, 6.8.0-1058.61~22.04.1, 6.8.0-1060.61, 6.8.0-1060.63+fips1, 6.8.0-1060.63~22.04.1, 6.8.0-1063.69, 6.8.0-1063.69+fips1, 6.8.1-1055.56, 6.8.1-1055.56~22.04.1
linux-aws (Ubuntu package) - addressed in versions 5.15.0.186.109, 5.15.0-186.196+fips1, 5.15.0.1106.103, 5.15.0-1106.110, 5.15.0.1107.107, 5.15.0-1107.108, 5.15.0.1112.108, 5.15.0.1112.115, 5.15.0-1112.119, 5.15.0-1112.119+fips1, 5.15.0-1112.119~20.04.1
linux-nvidia-tegra (Ubuntu package) - addressed in versions 5.15.0-1053.53, 5.15.0.1053.55, 5.15.0.1064.64, 5.15.0-1064.66, 6.8.0-1029.30
linux-nvidia-tegra-5.15 (Ubuntu package) - update to 5.15.0-1064.66~20.04.1
linux-intel-iot-realtime (Ubuntu package) - addressed in versions 5.15.0-1104.106, 5.15.0.1104.108, 5.15.0-1107.113~20.04.1
linux-ibm-5.15 (Ubuntu package) - update to 5.15.0-1106.110~20.04.1
linux-intel-iotg (Ubuntu package) - addressed in versions 5.15.0.1107.106, 5.15.0-1107.113
linux-azure (Ubuntu package) - addressed in versions 5.15.0.1109.105, 5.15.0-1109.115, 5.15.0.1117.115, 5.15.0-1117.126, 6.8.0-1063.71, 6.8.0-1063.71~22.04.1
linux-azure-5.15 (Ubuntu package) - addressed in versions 5.15.0-1109.115~20.04.1, 5.15.0-1117.126~20.04.1, 5.15.0-1117.126~20.04.2
linux-gcp-5.15 (Ubuntu package) - update to 5.15.0-1112.122~20.04.1
linux-azure-fips (Ubuntu package) - addressed in versions 5.15.0.1117.102, 5.15.0-1117.126+fips1, 6.8.0-134.134+fips1, 6.8.0-1062.69+fips1
linux-azure-fde (Ubuntu package) - addressed in versions 5.15.0-1117.126, 6.8.0-1062.69
linux-hwe-6.8 (Ubuntu package) - update to 6.8.0-136.136~22.04.1
linux-aws-6.8 (Ubuntu package) - addressed in versions 6.8.0-1045.48, 6.8.0-1057.58~22.04.1, 6.8.0-1058.61.1, 6.8.0-1058.64, 6.8.0-1060.61~22.04.1, 6.8.0-1060.63~22.04.1, 6.8.0-1063.69~22.04.1
linux-raspi (Ubuntu package) - update to 6.8.0-1060.64
linux-azure-fde-6.8 (Ubuntu package) - update to 6.8.0-1062.69~22.04.1
linux-raspi-realtime (Ubuntu package) - update to 6.8.0-2049.50

External References

Related Security Bulletins