Out-of-bounds read in Linux kernel - CVE-2026-64018

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Main Vulnerability Database Vulnerabilities #VU138632

Out-of-bounds read in Linux kernel - CVE-2026-64018

Published: July 20, 2026


Vulnerability identifier: #VU138632
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-2026-64018
CWE-ID: CWE-125
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

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

The vulnerability exists due to an out-of-bounds read in mana_hwc_rx_event_handler() when processing hardware-modifiable WQE contents from DMA-coherent memory. A local attacker can modify the derived rx_req_idx value to cause a denial of service.

In confidential VMs such as SEV-SNP and TDX, the affected DMA-coherent memory is shared unencrypted and hardware can modify WQE contents at any time.


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
kernel (Red Hat package)
kernel-rt (Red Hat package)
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-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-azure-fde-6.8 (Ubuntu package)
linux-azure-fde-6.17 (Ubuntu package)
linux-azure-6.17 (Ubuntu package)
linux-ibm (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-nvidia-bos (Ubuntu package)

How to mitigate CVE-2026-64018

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
kernel (Red Hat package) - addressed in versions 4.18.0-553.159.1.el8_10, 6.12.0-211.50.1.el10_2
kernel-rt (Red Hat package) - update to 4.18.0-553.159.1.rt7.500.el8_10
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
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, 7.0.0-1009.9, 7.0.0-1015.15
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
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-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, 7.0.0-1009.9, 7.0.0-1010.10
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, 6.8.0-1063.71+fips2
linux-azure-fde (Ubuntu package) - addressed in versions 5.15.0-1117.126, 6.8.0-1062.69
linux-azure-fde-6.8 (Ubuntu package) - update to 6.8.0-1062.69~22.04.1
linux-azure-fde-6.17 (Ubuntu package) - update to 6.17.0-1018.18~24.04.1
linux-azure-6.17 (Ubuntu package) - update to 6.17.0-1021.21~24.04.1
linux-ibm (Ubuntu package) - addressed in versions 7.0.0-1008.8, 7.0.0-1010.10
linux-nvidia (Ubuntu package) - addressed in versions 7.0.0-1016.16, 7.0.0-1016.16~24.04.1
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2016.16

External References

Related Security Bulletins