Out-of-bounds read in Linux kernel - CVE-2026-45856

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Main Vulnerability Database Vulnerabilities #VU132636

Out-of-bounds read in Linux kernel - CVE-2026-45856

Published: May 28, 2026


Vulnerability identifier: #VU132636
CSH Severity: Low
CVSS v4: 6.9 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-45856
CWE-ID: CWE-125
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local user to disclose sensitive information.

The vulnerability exists due to an out-of-bounds read in ib_uverbs_post_send() when processing a user-supplied wqe_size value. A local user can provide a crafted small wqe_size value to disclose sensitive information.

An excessively large wqe_size value can also trigger a warning in the memory allocation path.


Affected software

Linux kernel
Red Hat CodeReady Linux Builder for ARM 64
Red Hat Enterprise Linux for Real Time
Red Hat Enterprise Linux for Real Time for NFV
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for ARM 64
Red Hat CodeReady Linux Builder for x86_64
Red Hat CodeReady Linux Builder for Power, little endian
Ubuntu
openEuler
kernel (Red Hat package)
kernel-rt (Red Hat package)
bpftool
python3-perf-debuginfo
python3-perf
perf-debuginfo
perf
kernel-tools-devel
kernel-tools-debuginfo
kernel-source
kernel
bpftool-debuginfo
kernel-debuginfo
kernel-devel
kernel-tools
kernel-headers
kernel-debugsource
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-raspi (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-azure-fde-6.8 (Ubuntu package)
linux-raspi-realtime (Ubuntu package)

How to mitigate CVE-2026-45856

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
kernel (Red Hat package) - addressed in versions 4.18.0-553.171.1.el8_10, 5.14.0-687.54.1.el9_8
kernel-rt (Red Hat package) - update to 4.18.0-553.171.1.rt7.512.el8_10
bpftool - update to 5.10.0-317.0.0.220
python3-perf-debuginfo - update to 5.10.0-317.0.0.220
python3-perf - update to 5.10.0-317.0.0.220
perf-debuginfo - update to 5.10.0-317.0.0.220
perf - update to 5.10.0-317.0.0.220
kernel-tools-devel - update to 5.10.0-317.0.0.220
kernel-tools-debuginfo - update to 5.10.0-317.0.0.220
kernel-source - update to 5.10.0-317.0.0.220
kernel - update to 5.10.0-317.0.0.220
bpftool-debuginfo - update to 5.10.0-317.0.0.220
kernel-debuginfo - update to 5.10.0-317.0.0.220
kernel-devel - update to 5.10.0-317.0.0.220
kernel-tools - update to 5.10.0-317.0.0.220
kernel-headers - update to 5.10.0-317.0.0.220
kernel-debugsource - update to 5.10.0-317.0.0.220
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-raspi (Ubuntu package) - addressed in versions 5.15.0.1106.104, 5.15.0-1106.109, 6.8.0-1060.64
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-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