CVE-2026-46066: ceph: fix num_ops off-by-one when crypto allocation fails

Q: Which systems are exposed to this issue?

The affected scenario requires CephFS files protected with fscrypt. Exploitation is local and requires low privileges according to the CVSS vector, along with the ability to write the relevant files.

Q: What conditions trigger the kernel panic?

A dirty folio that is not first in a batch must fail crypto bounce-buffer allocation and be discontiguous from the preceding folio in the batch. The issue can be reproduced by writing an fscrypt-enabled CephFS file in a repeating 4 KiB written, 4 KiB skipped pattern while gradually increasing memory pressure.

Q: What is the observable impact?

The system can panic in ceph_submit_write() when its expected write-operation count does not match the number of submitted operations. The reported assertion is BUG_ON(ceph_wbc->op_idx + 1 != req->r_num_ops).

Published May 27, 2026

Updated

ceph: fix numops off-by-one when crypto allocation fails

Affected Software

172 affected componentsFixes available

Linux Linux kernel=6.18.16, =6.19.6, =7.0-rc1

Linux Linux kernel>=6.6<6.18.30

Linux Linux kernel>=6.19<7.0.4

debian/linux<6.12.115-2

6.12.115-2

debian/linux<7.0.4-1

7.0.4-1

linux/kernel>=6.6.0<6.6.160

6.6.160

linux/kernel>=6.7.0<6.12.114

6.12.114

linux/kernel>=6.13.0<6.18.30

6.18.30

linux/kernel>=6.19.0<7.0.4

7.0.4

debian/linux<=6.12.107-1

6.1.176-16.1.190-16.12.116-17.2.15-17.3.4-1

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-aws-6.8*

ubuntu/linux-azure-5.19*

ubuntu/linux-azure-6.2*

ubuntu/linux-azure-6.5*

ubuntu/linux-azure-6.8*

ubuntu/linux-azure-fde-5.19*

ubuntu/linux-azure-fde-6.2*

ubuntu/linux-azure-fde-6.8*

ubuntu/linux-gcp-5.19*

ubuntu/linux-gcp-6.2*

ubuntu/linux-gcp-6.5*

ubuntu/linux-gcp-6.8*

ubuntu/linux-hwe-5.19*

ubuntu/linux-hwe-6.2*

ubuntu/linux-hwe-6.5*

ubuntu/linux-ibm-6.8*

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-lowlatency-hwe-6.8*

ubuntu/linux-nvidia-6.2*

ubuntu/linux-nvidia-6.5*

ubuntu/linux-nvidia-6.8*

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-oracle-6.8*

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.19*

ubuntu/linux-riscv-6.5*

ubuntu/linux-riscv-6.8*

ubuntu/linux-starfive-5.19*

ubuntu/linux-starfive-6.2*

ubuntu/linux-starfive-6.5*

ubuntu/linux-realtime-6.8*

ubuntu/linux*

ubuntu/linux-aws*

ubuntu/linux-aws-6.14*

ubuntu/linux-aws-6.17*

ubuntu/linux-azure*

ubuntu/linux-azure-6.11*

ubuntu/linux-azure-6.14*

ubuntu/linux-azure-6.17*

ubuntu/linux-azure-fde*

ubuntu/linux-azure-fde-6.14*

ubuntu/linux-azure-fde-6.17*

ubuntu/linux-azure-nvidia*

ubuntu/linux-azure-nvidia-6.14*

ubuntu/linux-gcp*

ubuntu/linux-gcp-6.11*

ubuntu/linux-gcp-6.14*

ubuntu/linux-gke*

ubuntu/linux-gkeop*

ubuntu/linux-hwe-6.11*

ubuntu/linux-hwe-6.14*

ubuntu/linux-hwe-6.17*

ubuntu/linux-hwe-7.0<7.0.0-28.28~24.04.1

7.0.0-28.28~24.04.1

ubuntu/linux-ibm*

ubuntu/linux-lowlatency*

ubuntu/linux-lowlatency-hwe-6.11*

ubuntu/linux-nvidia*

ubuntu/linux-nvidia-6.11*

ubuntu/linux-nvidia-6.17*

ubuntu/linux-nvidia-lowlatency*

ubuntu/linux-nvidia-tegra*

ubuntu/linux-oem-6.11*

ubuntu/linux-oem-6.14*

ubuntu/linux-oem-6.17*

ubuntu/linux-oem-6.8*

ubuntu/linux-oracle*

ubuntu/linux-oracle-6.14*

ubuntu/linux-oracle-6.17*

ubuntu/linux-raspi*

ubuntu/linux-raspi-realtime*

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-6.14*

ubuntu/linux-riscv-6.17*

ubuntu/linux-vmware*

ubuntu/linux-xilinx*

ubuntu/linux-bluefield*

ubuntu/linux-raspi-realtime*

ubuntu/linux-realtime*

ubuntu/linux-realtime-6.14*

ubuntu/linux-realtime-6.17*

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux*

ubuntu/linux-aws*

ubuntu/linux-azure*

ubuntu/linux-azure-fde*

ubuntu/linux-gcp*

ubuntu/linux-oracle*

ubuntu/linux-raspi*

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux<7.0.0-27.27

7.0.0-27.27

ubuntu/linux-aws<7.0.0-1008.8

7.0.0-1008.8

ubuntu/linux-azure<7.0.0-1010.10

7.0.0-1010.10

ubuntu/linux-azure-fde<7.0.0-1009.9

7.0.0-1009.9

ubuntu/linux-gcp<7.0.0-1007.7

7.0.0-1007.7

ubuntu/linux-ibm<7.0.0-1009.9

7.0.0-1009.9

ubuntu/linux-nvidia<7.0.0-1013.13

7.0.0-1013.13

ubuntu/linux-oem-7.0<7.0.0-1008.8

7.0.0-1008.8

ubuntu/linux-oracle<7.0.0-1007.7

7.0.0-1007.7

ubuntu/linux-raspi<7.0.0-1014.14

7.0.0-1014.14

ubuntu/linux-realtime<7.0.0-27.27.1

7.0.0-27.27.1

ubuntu/linux-riscv<7.0.0-27.27.1

7.0.0-27.27.1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade debian/linux to a version that resolves this vulnerability.
Fixed in 6.12.115-2
Upgrade
Upgrade debian/linux to a version that resolves this vulnerability.
Fixed in 7.0.4-1
Upgrade
Upgrade linux/Kernel to a version that resolves this vulnerability.
Fixed in 6.6.160
Upgrade
Upgrade linux/Kernel to a version that resolves this vulnerability.
Fixed in 6.12.114
Upgrade
Upgrade linux/Kernel to a version that resolves this vulnerability.
Fixed in 6.18.30
Upgrade
Upgrade linux/Kernel to a version that resolves this vulnerability.
Fixed in 7.0.4
Upgrade
Upgrade ubuntu/linux-hwe-7.0 to a version that resolves this vulnerability.
Fixed in 7.0.0-28.28~24.04.1
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 7.0.0-27.27
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 7.0.0-1008.8
Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 7.0.0-1010.10
Upgrade
Upgrade ubuntu/linux-azure-fde to a version that resolves this vulnerability.
Fixed in 7.0.0-1009.9
Upgrade
Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 7.0.0-1007.7
Upgrade
Upgrade ubuntu/linux-ibm to a version that resolves this vulnerability.
Fixed in 7.0.0-1009.9
Upgrade
Upgrade ubuntu/linux-nvidia to a version that resolves this vulnerability.
Fixed in 7.0.0-1013.13
Upgrade
Upgrade ubuntu/linux-oem-7.0 to a version that resolves this vulnerability.
Fixed in 7.0.0-1008.8
Upgrade
Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 7.0.0-1007.7
Upgrade
Upgrade ubuntu/linux-raspi to a version that resolves this vulnerability.
Fixed in 7.0.0-1014.14
Upgrade
Upgrade ubuntu/linux-realtime to a version that resolves this vulnerability.
Fixed in 7.0.0-27.27.1
Upgrade
Upgrade ubuntu/linux-riscv to a version that resolves this vulnerability.
Fixed in 7.0.0-27.27.1
Upgrade
Upgrade debian/linux to a version that resolves this vulnerability.
Fixed in 6.1.176-1Fixed in 6.1.190-1Fixed in 6.12.116-1Fixed in 7.2.15-1Fixed in 7.3.4-1

Event History

May 27, 2026

CVE Published

via MITRE·12:57 PM

Data Sourced

via MITRE·12:57 PM

Description

Data Sourced

via OSV·12:57 PM

DescriptionAffected Software

Data Sourced

via NVD·02:17 PM

RemedyDescriptionSeverityWeaknessAffected Software

May 28, 2026

Data Sourced

via Microsoft·08:04 AM

DescriptionSeverityWeakness

Nov 12, 2026

Data Sourced

via OSV·05:25 PM

Severity

Parent advisories

This vulnerability appears in the following advisories.

DSA-6602

Frequently Asked Questions

Which systems are exposed to this issue?

The affected scenario requires CephFS files protected with fscrypt. Exploitation is local and requires low privileges according to the CVSS vector, along with the ability to write the relevant files.

What conditions trigger the kernel panic?

A dirty folio that is not first in a batch must fail crypto bounce-buffer allocation and be discontiguous from the preceding folio in the batch. The issue can be reproduced by writing an fscrypt-enabled CephFS file in a repeating 4 KiB written, 4 KiB skipped pattern while gradually increasing memory pressure.

What is the observable impact?

The system can panic in ceph_submit_write() when its expected write-operation count does not match the number of submitted operations. The reported assertion is BUG_ON(ceph_wbc->op_idx + 1 != req->r_num_ops).

What can be done before a fix is applied?

Avoid the stated trigger conditions where possible: writes to fscrypt-enabled CephFS files using alternating sparse 4 KiB write/skip patterns, particularly under increasing memory pressure. This reduces exposure to the documented reproduction path.

CVE-2026-46066: ceph: fix num_ops off-by-one when crypto allocation fails

Affected Software

Remediation

Event History

Parent advisories

Frequently Asked Questions

Which systems are exposed to this issue?

What conditions trigger the kernel panic?

What is the observable impact?

What can be done before a fix is applied?

Company

Resources

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