Double free in Linux kernel - CVE-2026-53294
Published: June 29, 2026
Vulnerability details
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to double free in mailbox-test channel handling when freeing reused channels. A local user can trigger the mailbox-test logic with an aliased RX and TX channel configuration to cause a denial of service.
The issue occurs in the special case where the RX channel is aliased to the TX channel with different MMIO.
Affected software
Ubuntu
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-azure-fips (Ubuntu package)
linux-azure-fde (Ubuntu package)
linux-fips (Ubuntu package)
linux-hwe-6.8 (Ubuntu package)
linux-ibm (Ubuntu package)
linux-oracle-6.8 (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-aws-6.8 (Ubuntu package)
linux-raspi (Ubuntu package)
linux-azure-fde-6.8 (Ubuntu package)
linux-gcp-fips (Ubuntu package)
linux-oem-7.0 (Ubuntu package)
linux-nvidia-bos (Ubuntu package)
How to mitigate CVE-2026-53294
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, 6.8.0-136.136, 6.8.0-1046.50, 6.8.0-1059.67, 6.8.0-1064.72, 6.8.0-1064.72~22.04.1, 6.8.1-1056.57, 6.8.1-1056.57~22.04.2, 7.0.0-28.28, 7.0.0-28.28.1, 7.0.0-1003.4, 7.0.0-1008.8
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, 6.8.0-1061.64+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-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-fips (Ubuntu package) - addressed in versions 6.8.0-136.136+fips2, 6.8.0-136.136.2, 6.8.0-136.136.2~22.04.1, 6.8.0-1058.61
linux-hwe-6.8 (Ubuntu package) - update to 6.8.0-136.136~22.04.1
linux-ibm (Ubuntu package) - addressed in versions 6.8.0-1030.31, 6.8.0-1033.34, 6.8.0-1061.62, 6.8.0-1061.62~22.04.1, 7.0.0-1008.8, 7.0.0-1010.10
linux-oracle-6.8 (Ubuntu package) - update to 6.8.0-1058.61~22.04.1
linux-nvidia (Ubuntu package) - addressed in versions 6.8.0-1059.62, 6.8.0-1059.62.1, 6.8.0-1059.62~22.04.1, 7.0.0-1016.16, 7.0.0-1016.16~24.04.1
linux-aws-6.8 (Ubuntu package) - addressed in versions 6.8.0-1061.64+fips1, 6.8.0-1061.64~22.04.1
linux-raspi (Ubuntu package) - addressed in versions 6.8.0-1061.65, 6.8.0-2050.52
linux-azure-fde-6.8 (Ubuntu package) - update to 6.8.0-1062.69~22.04.1
linux-gcp-fips (Ubuntu package) - update to 6.8.0-1064.72+fips1
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1009.9
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2016.16
External References
- https://git.kernel.org/stable/c/240c71a2aea36a1a4210f911a1c32ea88777e8e4
- https://git.kernel.org/stable/c/3afca89fae501dbd7421e1777b5b8f033b1d98d0
- https://git.kernel.org/stable/c/5c209299b0113e289e238fa5f2e8f00c59f76060
- https://git.kernel.org/stable/c/5d4f3d0f64f1016cb78b400a70b67df91fac99b5
- https://git.kernel.org/stable/c/82f6dcea46cf5de65c4ba7283f7c7b34de4a324d
- https://git.kernel.org/stable/c/88ebadbf0deefdaccdab868b44ff70a0a257f473
- https://git.kernel.org/stable/c/c494a11da45ad7ec9b0ff216c3e3ace351193bb6
- https://git.kernel.org/stable/c/fc0089f82c3e36060c2c79156bc2018bfb16b56b
Related Security Bulletins
- Double free in Linux kernel mailbox driver
- Ubuntu update for linux-oem-7.0
- Ubuntu update for linux
- Ubuntu update for linux
- Ubuntu update for linux-gcp-fips
- Ubuntu update for linux-nvidia-tegra-5.15
- Ubuntu update for linux
- Ubuntu update for linux-oracle-6.8
- Ubuntu update for linux-fips
- Ubuntu update for linux-ibm
- Ubuntu update for linux-nvidia-tegra
- Ubuntu update for linux-aws
- Ubuntu update for linux-nvidia
- Ubuntu update for linux-azure
- Ubuntu update for linux-azure-fde
- Ubuntu update for linux-azure
- Ubuntu update for linux-azure-fde-6.8
- Ubuntu update for linux-azure-fips
- Ubuntu update for linux-azure-fde
- Ubuntu update for linux-azure
- Ubuntu update for linux-aws
- Ubuntu update for linux-azure-5.15
- Ubuntu update for linux-hwe-6.8
- Ubuntu update for linux-aws-6.8
- Ubuntu update for linux-ibm
- Ubuntu update for linux-aws
- Ubuntu update for linux-azure-fips
- Ubuntu update for linux-intel-iot-realtime
- Ubuntu update for linux-intel-iotg
- Ubuntu update for linux-raspi
- Ubuntu update for linux-nvidia-bos
- Ubuntu update for linux-nvidia