UBUNTU-CVE-2026-93198: Medium severity ubuntu/linux-hwe-edge vulnerability

Q: Which deployments are exposed?

The issue applies to systems using dm-pcache that load persisted cache metadata. The affected Ubuntu kernel package families listed are linux-riscv, linux-realtime, linux-hwe-edge, linux-azure, linux-gcp, linux-azure-fde, linux-gke, and linux-aws-5.0.

Q: What would an attacker need to exploit this?

An attacker would need to provide or alter the cache device's persisted on-media metadata so that the dirty_tail chain points to a sequence of last ksets that does not terminate. The relevant on-media fields are protected only by crc32c using a fixed seed.

Q: What is the operational impact of a malicious cache image?

The writeback worker can repeatedly re-arm itself with no delay while following the non-terminating dirty_tail chain. This can continue indefinitely.

Q: How does the fix handle malformed persisted metadata?

The corrected load path walks the dirty_tail chain once using the same hop cap as cache_replay(). If the chain does not end within n_segs hops, loading the table fails with -EIO.

Published Sep 17, 2026

Updated

In the Linux kernel, the following vulnerability has been resolved: dm-pcache: validate the persisted dirtytail chain at load The writeback worker follows the persisted dirtytail chain, which is decoded from the cache device independently of the keytail chain that cachereplay() walks and bounds. A crafted image, whose on-media fields are authenticated only by a crc32c with a fixed seed, can aim dirtytail at a chain of last ksets that never terminates, so cachewritebackfn() re-arms itself with no delay forever. Walk the dirtytail chain once at load with the same hop cap cachereplay() uses and fail the table load with -EIO if it does not reach an end within nsegs hops.

Affected Software

126 affected componentsFixes available

ubuntu/linux-hwe-edge*

ubuntu/linux-aws-5.0*

ubuntu/linux-aws-5.3*

ubuntu/linux-azure*

ubuntu/linux-azure-5.3*

ubuntu/linux-azure-edge*

ubuntu/linux-gcp*

ubuntu/linux-gcp-5.3*

ubuntu/linux-gke-4.15*

ubuntu/linux-gke-5.4*

ubuntu/linux-gkeop-5.4*

ubuntu/linux-hwe*

ubuntu/linux-hwe-edge*

ubuntu/linux-oem*

ubuntu/linux-oracle-5.0*

ubuntu/linux-oracle-5.3*

ubuntu/linux-aws-5.11*

ubuntu/linux-aws-5.13*

ubuntu/linux-aws-5.8*

ubuntu/linux-azure-5.11*

ubuntu/linux-azure-5.13*

ubuntu/linux-azure-5.8*

ubuntu/linux-azure-fde*

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-5.8*

ubuntu/linux-intel-5.13*

ubuntu/linux-oem-5.10*

ubuntu/linux-oem-5.13*

ubuntu/linux-oem-5.6*

ubuntu/linux-oracle-5.11*

ubuntu/linux-oracle-5.13*

ubuntu/linux-oracle-5.8*

ubuntu/linux-raspi2*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.11*

ubuntu/linux-riscv-5.8*

ubuntu/linux-allwinner-5.19*

ubuntu/linux-aws-5.19*

ubuntu/linux-aws-6.2*

ubuntu/linux-aws-6.5*

ubuntu/linux-azure-5.19*

ubuntu/linux-azure-6.2*

ubuntu/linux-azure-6.5*

ubuntu/linux-azure-fde-5.19*

ubuntu/linux-azure-fde-6.2*

ubuntu/linux-gcp-5.19*

ubuntu/linux-gcp-6.2*

ubuntu/linux-gcp-6.5*

ubuntu/linux-hwe-5.19*

ubuntu/linux-hwe-6.2*

ubuntu/linux-hwe-6.5*

ubuntu/linux-intel-iot-realtime*

ubuntu/linux-lowlatency-hwe-5.19*

ubuntu/linux-lowlatency-hwe-6.2*

ubuntu/linux-lowlatency-hwe-6.5*

ubuntu/linux-nvidia-6.2*

ubuntu/linux-nvidia-6.5*

ubuntu/linux-oem-5.17*

ubuntu/linux-oem-6.0*

ubuntu/linux-oem-6.1*

ubuntu/linux-oem-6.5*

ubuntu/linux-oracle-6.5*

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.19*

ubuntu/linux-riscv-6.5*

ubuntu/linux-starfive-5.19*

ubuntu/linux-starfive-6.2*

ubuntu/linux-starfive-6.5*

ubuntu/linux-aws-6.14*

ubuntu/linux-aws-6.17*

ubuntu/linux-aws-7.0*

ubuntu/linux-azure-6.11*

ubuntu/linux-azure-6.14*

ubuntu/linux-azure-6.17*

ubuntu/linux-azure-7.0*

ubuntu/linux-azure-fde-6.14*

ubuntu/linux-azure-fde-6.17*

ubuntu/linux-azure-fde-7.0*

ubuntu/linux-azure-nvidia-6.14*

ubuntu/linux-gcp-6.11*

ubuntu/linux-gcp-6.14*

ubuntu/linux-gcp-7.0*

ubuntu/linux-hwe-6.11*

ubuntu/linux-hwe-6.14*

ubuntu/linux-hwe-7.0<7.0.0-42.42~24.04.1

7.0.0-42.42~24.04.1

ubuntu/linux-lowlatency-hwe-6.11*

ubuntu/linux-nvidia-6.11*

ubuntu/linux-nvidia-6.17*

ubuntu/linux-nvidia-7.0*

ubuntu/linux-oem-6.11*

ubuntu/linux-oem-6.14*

ubuntu/linux-oem-6.8*

ubuntu/linux-oracle-6.14*

ubuntu/linux-oracle-6.17*

ubuntu/linux-oracle-7.0*

ubuntu/linux-raspi-realtime*

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-6.14*

ubuntu/linux-riscv-6.17*

ubuntu/linux-riscv-7.0<7.0.0-42.42.1~24.04.1

7.0.0-42.42.1~24.04.1

ubuntu/linux-realtime-6.14*

ubuntu/linux-realtime-6.17*

ubuntu/linux<7.0.0-42.42

7.0.0-42.42

ubuntu/linux-aws<7.0.0-1016.17

7.0.0-1016.17

ubuntu/linux-azure*

ubuntu/linux-azure-fde*

ubuntu/linux-gcp<7.0.0-1016.18

7.0.0-1016.18

ubuntu/linux-gke*

ubuntu/linux-ibm<7.0.0-1017.17

7.0.0-1017.17

ubuntu/linux-nvidia*

ubuntu/linux-nvidia-bos*

ubuntu/linux-oem-7.0<7.0.0-1017.17

7.0.0-1017.17

ubuntu/linux-oracle<7.0.0-1015.16

7.0.0-1015.16

ubuntu/linux-raspi*

ubuntu/linux-realtime*

ubuntu/linux-riscv<7.0.0-42.42.1

7.0.0-42.42.1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade ubuntu/linux-hwe-7.0 to a version that resolves this vulnerability.
Fixed in 7.0.0-42.42~24.04.1
Upgrade
Upgrade ubuntu/linux-riscv-7.0 to a version that resolves this vulnerability.
Fixed in 7.0.0-42.42.1~24.04.1
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 7.0.0-42.42
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 7.0.0-1016.17
Upgrade
Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 7.0.0-1016.18
Upgrade
Upgrade ubuntu/linux-ibm to a version that resolves this vulnerability.
Fixed in 7.0.0-1017.17
Upgrade
Upgrade ubuntu/linux-oem-7.0 to a version that resolves this vulnerability.
Fixed in 7.0.0-1017.17
Upgrade
Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 7.0.0-1015.16
Upgrade
Upgrade ubuntu/linux-riscv to a version that resolves this vulnerability.
Fixed in 7.0.0-42.42.1
Compensating control
At load time, walk the persisted dirty_tail chain once using the same hop cap as cache_replay(); fail the table load with -EIO if the chain does not reach an end within n_segs hops.

Event History

Sep 17, 2026

CVE Published

via OSV·05:18 PM

Data Sourced

via OSV·05:18 PM

DescriptionSeverityAffected Software

Frequently Asked Questions

Which deployments are exposed?

The issue applies to systems using dm-pcache that load persisted cache metadata. The affected Ubuntu kernel package families listed are linux-riscv, linux-realtime, linux-hwe-edge, linux-azure, linux-gcp, linux-azure-fde, linux-gke, and linux-aws-5.0.

What would an attacker need to exploit this?

An attacker would need to provide or alter the cache device's persisted on-media metadata so that the dirty_tail chain points to a sequence of last ksets that does not terminate. The relevant on-media fields are protected only by crc32c using a fixed seed.

What is the operational impact of a malicious cache image?

The writeback worker can repeatedly re-arm itself with no delay while following the non-terminating dirty_tail chain. This can continue indefinitely.

How does the fix handle malformed persisted metadata?

The corrected load path walks the dirty_tail chain once using the same hop cap as cache_replay(). If the chain does not end within n_segs hops, loading the table fails with -EIO.

UBUNTU-CVE-2026-93198: Medium severity ubuntu/linux-hwe-edge vulnerability

Affected Software

Remediation

Event History

Frequently Asked Questions

Which deployments are exposed?

What would an attacker need to exploit this?

What is the operational impact of a malicious cache image?

How does the fix handle malformed persisted metadata?

Company

Resources

Contact

Frequently Asked Questions

Which deployments are exposed?

What would an attacker need to exploit this?

What is the operational impact of a malicious cache image?

How does the fix handle malformed persisted metadata?