UBUNTU-CVE-2025-21820: Medium severity ubuntu/linux-azure vulnerability

Q: Which systems are exposed to this issue?

Systems running one of the listed Ubuntu kernel packages are potentially exposed when they use the Xilinx PS UART driver (xilinx_uartps). The affected package list includes linux, linux-azure, linux-aws-fips, linux-azure-fips, linux-gcp, linux-gcp-fips, linux-oracle, and linux-fips.

Q: What does exploitation require?

The issue involves a kernel locking sequence between the Xilinx UART interrupt handler and console output while SysRq handling is involved. The provided data does not identify a remote attack path, required privileges, or user interaction; the vector is listed as physical and privileges required as none.

Q: What is the likely impact if the issue is triggered?

The described race can result in a deadlock. The supplied severity vector indicates an availability impact only, with high availability impact and no stated confidentiality or integrity impact.

Q: How was the deadlock addressed?

The fix splits SysRq processing into preparation performed while holding the UART port lock and handling deferred until after that lock is released. This prevents the problematic lock ordering between the port lock and the console lock.

Published Feb 27, 2025

Updated

In the Linux kernel, the following vulnerability has been resolved: tty: xilinxuartps: split sysrq handling lockdep detects the following circular locking dependency: CPU 0 CPU 1 ========================== ============================ cdnsuartisr() printk() uartportlock(port) consolelock() cdnsuartconsolewrite() if (!port->sysrq) uartportlock(port) uarthandlebreak() port->sysrq = ... uarthandlesysrqchar() printk() consolelock() The fixed commit attempts to avoid this situation by only taking the port lock in cdnsuartconsolewrite if port->sysrq unset. However, if (as shown above) cdnsuartconsolewrite runs before port->sysrq is set, then it will try to take the port lock anyway. This may result in a deadlock. Fix this by splitting sysrq handling into two parts. We use the prepare helper under the port lock and defer handling until we release the lock.

Affected Software

200 affected componentsFixes available

ubuntu/linux-azure*

ubuntu/linux-aws-hwe*

ubuntu/linux-azure*

ubuntu/linux-gcp*

ubuntu/linux-hwe*

ubuntu/linux-hwe-edge*

ubuntu/linux-oracle*

ubuntu/linux*

ubuntu/linux-aws*

ubuntu/linux-aws-5.0*

ubuntu/linux-aws-5.3*

ubuntu/linux-aws-5.4*

ubuntu/linux-azure*

ubuntu/linux-azure-4.15*

ubuntu/linux-azure-5.3*

ubuntu/linux-azure-5.4*

ubuntu/linux-azure-edge*

ubuntu/linux-gcp*

ubuntu/linux-gcp-4.15*

ubuntu/linux-gcp-5.3*

ubuntu/linux-gcp-5.4*

ubuntu/linux-gke-4.15*

ubuntu/linux-gke-5.4*

ubuntu/linux-gkeop-5.4*

ubuntu/linux-hwe*

ubuntu/linux-hwe-5.4*

ubuntu/linux-hwe-edge*

ubuntu/linux-ibm-5.4*

ubuntu/linux-kvm*

ubuntu/linux-oem*

ubuntu/linux-oracle*

ubuntu/linux-oracle-5.0*

ubuntu/linux-oracle-5.3*

ubuntu/linux-oracle-5.4*

ubuntu/linux-raspi-5.4*

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux-aws-5.15<5.15.0-1084.91~20.04.1

5.15.0-1084.91~20.04.1

ubuntu/linux-azure-5.15<5.15.0-1089.98~20.04.1

5.15.0-1089.98~20.04.1

ubuntu/linux-gcp-5.15<5.15.0-1083.92~20.04.1

5.15.0-1083.92~20.04.1

ubuntu/linux-ibm-5.15<5.15.0-1076.79~20.04.1

5.15.0-1076.79~20.04.1

ubuntu/linux-intel-iotg-5.15<5.15.0-1079.85~20.04.1

5.15.0-1079.85~20.04.1

ubuntu/linux-lowlatency-hwe-5.15<5.15.0-140.150~20.04.1

5.15.0-140.150~20.04.1

ubuntu/linux-oracle-5.15<5.15.0-1081.87~20.04.1

5.15.0-1081.87~20.04.1

ubuntu/linux-riscv-5.15<5.15.0-1079.83~20.04.1

5.15.0-1079.83~20.04.1

ubuntu/linux*

ubuntu/linux-aws*

ubuntu/linux-aws-5.11*

ubuntu/linux-aws-5.13*

ubuntu/linux-aws-5.8*

ubuntu/linux-azure*

ubuntu/linux-azure-5.11*

ubuntu/linux-azure-5.13*

ubuntu/linux-azure-5.8*

ubuntu/linux-azure-fde*

ubuntu/linux-bluefield*

ubuntu/linux-gcp*

ubuntu/linux-gcp-5.11*

ubuntu/linux-gcp-5.13*

ubuntu/linux-gcp-5.8*

ubuntu/linux-gke*

ubuntu/linux-gke-5.15*

ubuntu/linux-gkeop*

ubuntu/linux-gkeop-5.15*

ubuntu/linux-hwe-5.11*

ubuntu/linux-hwe-5.13*

ubuntu/linux-hwe-5.15<5.15.0-142.152~20.04.1

5.15.0-142.152~20.04.1

ubuntu/linux-hwe-5.8*

ubuntu/linux-ibm*

ubuntu/linux-intel-5.13*

ubuntu/linux-iot*

ubuntu/linux-kvm*

ubuntu/linux-nvidia-tegra-5.15<5.15.0-1039.39~20.04.1

5.15.0-1039.39~20.04.1

ubuntu/linux-oem-5.10*

ubuntu/linux-oem-5.13*

ubuntu/linux-oem-5.6*

ubuntu/linux-oracle*

ubuntu/linux-oracle-5.11*

ubuntu/linux-oracle-5.13*

ubuntu/linux-oracle-5.8*

ubuntu/linux-raspi*

ubuntu/linux-raspi2*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.11*

ubuntu/linux-riscv-5.8*

ubuntu/linux-xilinx-zynqmp*

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux<5.15.0-140.150

5.15.0-140.150

ubuntu/linux-allwinner-5.19*

ubuntu/linux-aws<5.15.0-1084.91

5.15.0-1084.91

ubuntu/linux-aws-5.19*

ubuntu/linux-aws-6.2*

ubuntu/linux-aws-6.5*

ubuntu/linux-aws-6.8<6.8.0-1032.34~22.04.1

6.8.0-1032.34~22.04.1

ubuntu/linux-azure<5.15.0-1089.98

5.15.0-1089.98

ubuntu/linux-azure-5.19*

ubuntu/linux-azure-6.2*

ubuntu/linux-azure-6.5*

ubuntu/linux-azure-6.8<6.8.0-1034.39~22.04.1

6.8.0-1034.39~22.04.1

ubuntu/linux-azure-fde<5.15.0-1089.98.1

5.15.0-1089.98.1

ubuntu/linux-azure-fde-5.19*

ubuntu/linux-azure-fde-6.2*

ubuntu/linux-gcp<5.15.0-1083.92

5.15.0-1083.92

ubuntu/linux-gcp-5.19*

ubuntu/linux-gcp-6.2*

ubuntu/linux-gcp-6.5*

ubuntu/linux-gcp-6.8<6.8.0-1033.35~22.04.1

6.8.0-1033.35~22.04.1

ubuntu/linux-gke<5.15.0-1081.87

5.15.0-1081.87

ubuntu/linux-gkeop<5.15.0-1066.74

5.15.0-1066.74

ubuntu/linux-hwe-5.19*

ubuntu/linux-hwe-6.2*

ubuntu/linux-hwe-6.5*

ubuntu/linux-hwe-6.8<6.8.0-64.67~22.04.1

6.8.0-64.67~22.04.1

ubuntu/linux-ibm<5.15.0-1076.79

5.15.0-1076.79

ubuntu/linux-ibm-6.8<6.8.0-1029.29~22.04.1

6.8.0-1029.29~22.04.1

ubuntu/linux-intel-iot-realtime*

ubuntu/linux-intel-iotg<5.15.0-1079.85

5.15.0-1079.85

ubuntu/linux-kvm<5.15.0-1080.85

5.15.0-1080.85

ubuntu/linux-lowlatency<5.15.0-140.150

5.15.0-140.150

ubuntu/linux-lowlatency-hwe-5.19*

ubuntu/linux-lowlatency-hwe-6.2*

ubuntu/linux-lowlatency-hwe-6.5*

ubuntu/linux-lowlatency-hwe-6.8<6.8.0-64.67.1~22.04.1

6.8.0-64.67.1~22.04.1

ubuntu/linux-nvidia<5.15.0-1078.79

5.15.0-1078.79

ubuntu/linux-nvidia-6.2*

ubuntu/linux-nvidia-6.5*

ubuntu/linux-nvidia-6.8<6.8.0-1031.34~22.04.1

6.8.0-1031.34~22.04.1

ubuntu/linux-nvidia-tegra<5.15.0-1037.37

5.15.0-1037.37

ubuntu/linux-nvidia-tegra-igx<5.15.0-1026.26

5.15.0-1026.26

ubuntu/linux-oem-5.17*

ubuntu/linux-oem-6.0*

ubuntu/linux-oem-6.1*

ubuntu/linux-oem-6.5*

ubuntu/linux-oracle<5.15.0-1081.87

5.15.0-1081.87

ubuntu/linux-oracle-6.5*

ubuntu/linux-oracle-6.8<6.8.0-1029.30~22.04.1

6.8.0-1029.30~22.04.1

ubuntu/linux-raspi<5.15.0-1078.81

5.15.0-1078.81

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.19*

ubuntu/linux-riscv-6.5*

ubuntu/linux-riscv-6.8<6.8.0-64.67~22.04.1

6.8.0-64.67~22.04.1

ubuntu/linux-starfive-5.19*

ubuntu/linux-starfive-6.2*

ubuntu/linux-starfive-6.5*

ubuntu/linux-xilinx-zynqmp<5.15.0-1050.54

5.15.0-1050.54

ubuntu/linux-bluefield<5.15.0-1066.68

5.15.0-1066.68

ubuntu/linux-intel-iot-realtime<5.15.0-1077.79

5.15.0-1077.79

ubuntu/linux-realtime<5.15.0-1084.93

5.15.0-1084.93

ubuntu/linux-realtime-6.8<6.8.1-1025.26~22.04.1

6.8.1-1025.26~22.04.1

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux-aws-fips<5.15.0-1084.91+fips1

5.15.0-1084.91+fips1

ubuntu/linux-azure-fips<5.15.0-1089.98+fips1

5.15.0-1089.98+fips1

ubuntu/linux-fips<5.15.0-140.150+fips1

5.15.0-140.150+fips1

ubuntu/linux-gcp-fips<5.15.0-1083.92+fips1

5.15.0-1083.92+fips1

ubuntu/linux<6.8.0-64.67

6.8.0-64.67

ubuntu/linux-aws<6.8.0-1032.34

6.8.0-1032.34

ubuntu/linux-azure<6.8.0-1034.39

6.8.0-1034.39

ubuntu/linux-azure-6.11<6.11.0-1015.15~24.04.1

6.11.0-1015.15~24.04.1

ubuntu/linux-azure-nvidia<6.8.0-1022.23

6.8.0-1022.23

ubuntu/linux-gcp<6.8.0-1033.35

6.8.0-1033.35

ubuntu/linux-gcp-6.11<6.11.0-1015.15~24.04.1

6.11.0-1015.15~24.04.1

ubuntu/linux-gke<6.8.0-1028.32

6.8.0-1028.32

ubuntu/linux-gkeop<6.8.0-1015.17

6.8.0-1015.17

ubuntu/linux-hwe-6.11<6.11.0-26.26~24.04.1

6.11.0-26.26~24.04.1

ubuntu/linux-ibm<6.8.0-1029.29

6.8.0-1029.29

ubuntu/linux-lowlatency<6.8.0-64.67.1

6.8.0-64.67.1

ubuntu/linux-lowlatency-hwe-6.11<6.11.0-1014.15~24.04.1

6.11.0-1014.15~24.04.1

ubuntu/linux-nvidia<6.8.0-1031.34

6.8.0-1031.34

ubuntu/linux-nvidia-6.11<6.11.0-1010.10

6.11.0-1010.10

ubuntu/linux-nvidia-lowlatency<6.8.0-1031.34.1

6.8.0-1031.34.1

ubuntu/linux-nvidia-tegra<6.8.0-1008.8

6.8.0-1008.8

ubuntu/linux-oem-6.11<6.11.0-1022.22

6.11.0-1022.22

ubuntu/linux-oem-6.8<6.8.0-1031.31

6.8.0-1031.31

ubuntu/linux-oracle<6.8.0-1029.30

6.8.0-1029.30

ubuntu/linux-raspi<6.8.0-1031.35

6.8.0-1031.35

ubuntu/linux-raspi-realtime*

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-xilinx<6.8.0-1017.18

6.8.0-1017.18

ubuntu/linux-raspi-realtime<6.8.0-2026.27

6.8.0-2026.27

ubuntu/linux-realtime<6.8.1-1025.26

6.8.1-1025.26

ubuntu/linux-fips<6.8.0-78.78+fips1

6.8.0-78.78+fips1

ubuntu/linux-vmware*

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade ubuntu/linux-aws-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1084.91~20.04.1
Upgrade
Upgrade ubuntu/linux-azure-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1089.98~20.04.1
Upgrade
Upgrade ubuntu/linux-gcp-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1083.92~20.04.1
Upgrade
Upgrade ubuntu/linux-ibm-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1076.79~20.04.1
Upgrade
Upgrade ubuntu/linux-intel-iotg-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1079.85~20.04.1
Upgrade
Upgrade ubuntu/linux-lowlatency-hwe-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-140.150~20.04.1
Upgrade
Upgrade ubuntu/linux-oracle-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1081.87~20.04.1
Upgrade
Upgrade ubuntu/linux-riscv-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1079.83~20.04.1
Upgrade
Upgrade ubuntu/linux-hwe-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-142.152~20.04.1
Upgrade
Upgrade ubuntu/linux-nvidia-tegra-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1039.39~20.04.1
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 5.15.0-140.150
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 5.15.0-1084.91
Upgrade
Upgrade ubuntu/linux-aws-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1032.34~22.04.1
Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 5.15.0-1089.98
Upgrade
Upgrade ubuntu/linux-azure-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1034.39~22.04.1
Upgrade
Upgrade ubuntu/linux-azure-fde to a version that resolves this vulnerability.
Fixed in 5.15.0-1089.98.1
Upgrade
Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 5.15.0-1083.92
Upgrade
Upgrade ubuntu/linux-gcp-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1033.35~22.04.1
Upgrade
Upgrade ubuntu/linux-gke to a version that resolves this vulnerability.
Fixed in 5.15.0-1081.87
Upgrade
Upgrade ubuntu/linux-gkeop to a version that resolves this vulnerability.
Fixed in 5.15.0-1066.74
Upgrade
Upgrade ubuntu/linux-hwe-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-64.67~22.04.1
Upgrade
Upgrade ubuntu/linux-ibm to a version that resolves this vulnerability.
Fixed in 5.15.0-1076.79
Upgrade
Upgrade ubuntu/linux-ibm-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1029.29~22.04.1
Upgrade
Upgrade ubuntu/linux-intel-iotg to a version that resolves this vulnerability.
Fixed in 5.15.0-1079.85
Upgrade
Upgrade ubuntu/linux-kvm to a version that resolves this vulnerability.
Fixed in 5.15.0-1080.85
Upgrade
Upgrade ubuntu/linux-lowlatency to a version that resolves this vulnerability.
Fixed in 5.15.0-140.150
Upgrade
Upgrade ubuntu/linux-lowlatency-hwe-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-64.67.1~22.04.1
Upgrade
Upgrade ubuntu/linux-nvidia to a version that resolves this vulnerability.
Fixed in 5.15.0-1078.79
Upgrade
Upgrade ubuntu/linux-nvidia-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1031.34~22.04.1
Upgrade
Upgrade ubuntu/linux-nvidia-tegra to a version that resolves this vulnerability.
Fixed in 5.15.0-1037.37
Upgrade
Upgrade ubuntu/linux-nvidia-tegra-igx to a version that resolves this vulnerability.
Fixed in 5.15.0-1026.26
Upgrade
Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 5.15.0-1081.87
Upgrade
Upgrade ubuntu/linux-oracle-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1029.30~22.04.1
Upgrade
Upgrade ubuntu/linux-raspi to a version that resolves this vulnerability.
Fixed in 5.15.0-1078.81
Upgrade
Upgrade ubuntu/linux-riscv-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-64.67~22.04.1
Upgrade
Upgrade ubuntu/linux-xilinx-zynqmp to a version that resolves this vulnerability.
Fixed in 5.15.0-1050.54
Upgrade
Upgrade ubuntu/linux-bluefield to a version that resolves this vulnerability.
Fixed in 5.15.0-1066.68
Upgrade
Upgrade ubuntu/linux-intel-iot-realtime to a version that resolves this vulnerability.
Fixed in 5.15.0-1077.79
Upgrade
Upgrade ubuntu/linux-realtime to a version that resolves this vulnerability.
Fixed in 5.15.0-1084.93
Upgrade
Upgrade ubuntu/linux-realtime-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.1-1025.26~22.04.1
Upgrade
Upgrade ubuntu/linux-aws-fips to a version that resolves this vulnerability.
Fixed in 5.15.0-1084.91+fips1
Upgrade
Upgrade ubuntu/linux-azure-fips to a version that resolves this vulnerability.
Fixed in 5.15.0-1089.98+fips1
Upgrade
Upgrade ubuntu/linux-fips to a version that resolves this vulnerability.
Fixed in 5.15.0-140.150+fips1
Upgrade
Upgrade ubuntu/linux-gcp-fips to a version that resolves this vulnerability.
Fixed in 5.15.0-1083.92+fips1
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 6.8.0-64.67
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 6.8.0-1032.34
Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 6.8.0-1034.39
Upgrade
Upgrade ubuntu/linux-azure-6.11 to a version that resolves this vulnerability.
Fixed in 6.11.0-1015.15~24.04.1
Upgrade
Upgrade ubuntu/linux-azure-nvidia to a version that resolves this vulnerability.
Fixed in 6.8.0-1022.23
Upgrade
Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 6.8.0-1033.35
Upgrade
Upgrade ubuntu/linux-gcp-6.11 to a version that resolves this vulnerability.
Fixed in 6.11.0-1015.15~24.04.1
Upgrade
Upgrade ubuntu/linux-gke to a version that resolves this vulnerability.
Fixed in 6.8.0-1028.32
Upgrade
Upgrade ubuntu/linux-gkeop to a version that resolves this vulnerability.
Fixed in 6.8.0-1015.17
Upgrade
Upgrade ubuntu/linux-hwe-6.11 to a version that resolves this vulnerability.
Fixed in 6.11.0-26.26~24.04.1
Upgrade
Upgrade ubuntu/linux-ibm to a version that resolves this vulnerability.
Fixed in 6.8.0-1029.29
Upgrade
Upgrade ubuntu/linux-lowlatency to a version that resolves this vulnerability.
Fixed in 6.8.0-64.67.1
Upgrade
Upgrade ubuntu/linux-lowlatency-hwe-6.11 to a version that resolves this vulnerability.
Fixed in 6.11.0-1014.15~24.04.1
Upgrade
Upgrade ubuntu/linux-nvidia to a version that resolves this vulnerability.
Fixed in 6.8.0-1031.34
Upgrade
Upgrade ubuntu/linux-nvidia-6.11 to a version that resolves this vulnerability.
Fixed in 6.11.0-1010.10
Upgrade
Upgrade ubuntu/linux-nvidia-lowlatency to a version that resolves this vulnerability.
Fixed in 6.8.0-1031.34.1
Upgrade
Upgrade ubuntu/linux-nvidia-tegra to a version that resolves this vulnerability.
Fixed in 6.8.0-1008.8
Upgrade
Upgrade ubuntu/linux-oem-6.11 to a version that resolves this vulnerability.
Fixed in 6.11.0-1022.22
Upgrade
Upgrade ubuntu/linux-oem-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1031.31
Upgrade
Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 6.8.0-1029.30
Upgrade
Upgrade ubuntu/linux-raspi to a version that resolves this vulnerability.
Fixed in 6.8.0-1031.35
Upgrade
Upgrade ubuntu/linux-xilinx to a version that resolves this vulnerability.
Fixed in 6.8.0-1017.18
Upgrade
Upgrade ubuntu/linux-raspi-realtime to a version that resolves this vulnerability.
Fixed in 6.8.0-2026.27
Upgrade
Upgrade ubuntu/linux-realtime to a version that resolves this vulnerability.
Fixed in 6.8.1-1025.26
Upgrade
Upgrade ubuntu/linux-fips to a version that resolves this vulnerability.
Fixed in 6.8.0-78.78+fips1

Event History

Feb 27, 2025

CVE Published

via OSV·08:16 PM

Data Sourced

via OSV·08:16 PM

DescriptionSeverityAffected Software

Frequently Asked Questions

Which systems are exposed to this issue?

Systems running one of the listed Ubuntu kernel packages are potentially exposed when they use the Xilinx PS UART driver (xilinx_uartps). The affected package list includes linux, linux-azure, linux-aws-fips, linux-azure-fips, linux-gcp, linux-gcp-fips, linux-oracle, and linux-fips.

What does exploitation require?

The issue involves a kernel locking sequence between the Xilinx UART interrupt handler and console output while SysRq handling is involved. The provided data does not identify a remote attack path, required privileges, or user interaction; the vector is listed as physical and privileges required as none.

What is the likely impact if the issue is triggered?

The described race can result in a deadlock. The supplied severity vector indicates an availability impact only, with high availability impact and no stated confidentiality or integrity impact.

How was the deadlock addressed?

The fix splits SysRq processing into preparation performed while holding the UART port lock and handling deferred until after that lock is released. This prevents the problematic lock ordering between the port lock and the console lock.

UBUNTU-CVE-2025-21820: Medium severity ubuntu/linux-azure vulnerability

Affected Software

Remediation

Event History

Frequently Asked Questions

Which systems are exposed to this issue?

What does exploitation require?

What is the likely impact if the issue is triggered?

How was the deadlock addressed?

Company

Resources

Contact

Frequently Asked Questions

Which systems are exposed to this issue?

What does exploitation require?

What is the likely impact if the issue is triggered?

How was the deadlock addressed?