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6.3
CVE-2026-90263: Linux btrfs can change ACLs on read‑only volumes
CVE-2026-90263 · published 1 month ago
Summary
The btrfs file system in the Linux kernel may allow access control list (ACL) changes even when the volume is set to read‑only. This could let users modify permissions on data that should be protected from any writes. Apply the latest kernel updates for the listed Linux distributions to ensure the read‑only check is enforced.
What to do
- Update debian linux to version 7.2.6-1.
- Update linux kernel to version 7.2.6.
- Update bellsoft linux-lts to version 6.18.58-r0.
- Update bellsoft linux-lts to version 6.12.115-r0.
- Update canonical linux-hwe-7.0 to version 7.0.0-42.42~24.04.1.
- Update canonical linux-riscv-7.0 to version 7.0.0-42.42.1~24.04.1.
- Update canonical linux to version 7.0.0-42.42.
- Update canonical linux-aws to version 7.0.0-1016.17.
- Update canonical linux-gcp to version 7.0.0-1016.18.
- Update canonical linux-ibm to version 7.0.0-1017.17.
- Update canonical linux-oem-7.0 to version 7.0.0-1017.17.
- Update canonical linux-oracle to version 7.0.0-1015.16.
- Update canonical linux-riscv to version 7.0.0-42.42.1.
- Update bellsoft linux-lts to version 6.1.191-r0.
Affected software
| Ecosystem | Vendor | Product | Affected versions |
|---|---|---|---|
| Debian:14 | debian | linux |
< 7.2.6-1 Fix: upgrade to 7.2.6-1
|
| Debian:12 | debian | linux | All versions |
| Ubuntu:Pro:14.04:LTS | canonical | linux | All versions |
| Ubuntu:Pro:14.04:LTS | canonical | linux-aws | All versions |
| Ubuntu:Pro:14.04:LTS | canonical | linux-azure | All versions |
| Ubuntu:Pro:14.04:LTS | canonical | linux-lts-xenial | All versions |
| Ubuntu:Pro:16.04:LTS | canonical | linux-aws-hwe | All versions |
| Ubuntu:Pro:16.04:LTS | canonical | linux-gcp | All versions |
| Ubuntu:Pro:16.04:LTS | canonical | linux-hwe | All versions |
| Ubuntu:16.04:LTS | canonical | linux-hwe-edge | All versions |
| Ubuntu:Pro:16.04:LTS | canonical | linux-kvm | All versions |
| Ubuntu:Pro:16.04:LTS | canonical | linux-oracle | All versions |
| Ubuntu:Pro:FIPS:16.04:LTS | canonical | linux-fips | All versions |
| Ubuntu:18.04:LTS | canonical | linux-aws-5.0 | All versions |
| Ubuntu:18.04:LTS | canonical | linux-aws-5.3 | All versions |
| Ubuntu:Pro:18.04:LTS | canonical | linux-aws-5.4 | All versions |
| Ubuntu:Pro:18.04:LTS | canonical | linux-azure-4.15 | All versions |
| Ubuntu:18.04:LTS | canonical | linux-azure-5.3 | All versions |
| Ubuntu:Pro:18.04:LTS | canonical | linux-azure-5.4 | All versions |
| Ubuntu:18.04:LTS | canonical | linux-azure-edge | All versions |
| Ubuntu:Pro:18.04:LTS | canonical | linux-gcp-4.15 | All versions |
| Ubuntu:18.04:LTS | canonical | linux-gcp-5.3 | All versions |
| Ubuntu:Pro:18.04:LTS | canonical | linux-gcp-5.4 | All versions |
| Ubuntu:18.04:LTS | canonical | linux-gke-4.15 | All versions |
| Ubuntu:18.04:LTS | canonical | linux-gke-5.4 | All versions |
| Ubuntu:18.04:LTS | canonical | linux-gkeop-5.4 | All versions |
| Ubuntu:Pro:18.04:LTS | canonical | linux-hwe-5.4 | All versions |
| Ubuntu:Pro:18.04:LTS | canonical | linux-ibm-5.4 | All versions |
| Ubuntu:18.04:LTS | canonical | linux-oem | All versions |
| Ubuntu:18.04:LTS | canonical | linux-oracle-5.0 | All versions |
| Ubuntu:18.04:LTS | canonical | linux-oracle-5.3 | All versions |
| Ubuntu:Pro:18.04:LTS | canonical | linux-oracle-5.4 | All versions |
| Ubuntu:Pro:18.04:LTS | canonical | linux-raspi-5.4 | All versions |
| Ubuntu:Pro:FIPS-updates:18.04:LTS | canonical | linux-aws-fips | All versions |
| Ubuntu:Pro:FIPS-updates:18.04:LTS | canonical | linux-azure-fips | All versions |
| Ubuntu:Pro:FIPS-updates:18.04:LTS | canonical | linux-gcp-fips | All versions |
| Ubuntu:20.04:LTS | canonical | linux-aws-5.11 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-aws-5.13 | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-aws-5.15 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-aws-5.8 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-azure-5.11 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-azure-5.13 | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-azure-5.15 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-azure-5.8 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-azure-fde | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-azure-fde-5.15 | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-bluefield | All versions |
| Ubuntu:20.04:LTS | canonical | linux-gcp-5.11 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-gcp-5.13 | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-gcp-5.15 | All versions |
Showing 50 of 182. Show the rest
| Ecosystem | Vendor | Product | Affected versions |
|---|---|---|---|
| Ubuntu:20.04:LTS | canonical | linux-gcp-5.8 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-gke | All versions |
| Ubuntu:20.04:LTS | canonical | linux-gke-5.15 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-gkeop | All versions |
| Ubuntu:20.04:LTS | canonical | linux-gkeop-5.15 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-hwe-5.11 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-hwe-5.13 | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-hwe-5.15 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-hwe-5.8 | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-ibm | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-ibm-5.15 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-intel-5.13 | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-intel-iotg-5.15 | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-iot | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-lowlatency-hwe-5.15 | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-nvidia-tegra-5.15 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-oem-5.10 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-oem-5.13 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-oem-5.14 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-oem-5.6 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-oracle-5.11 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-oracle-5.13 | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-oracle-5.15 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-oracle-5.8 | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-raspi | All versions |
| Ubuntu:20.04:LTS | canonical | linux-raspi2 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-riscv | All versions |
| Ubuntu:20.04:LTS | canonical | linux-riscv-5.11 | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-riscv-5.15 | All versions |
| Ubuntu:20.04:LTS | canonical | linux-riscv-5.8 | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | linux-xilinx-zynqmp | All versions |
| Ubuntu:22.04:LTS | canonical | linux-allwinner-5.19 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-aws-5.19 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-aws-6.2 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-aws-6.5 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-aws-6.8 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-azure-5.19 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-azure-6.2 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-azure-6.5 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-azure-6.8 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-azure-fde-5.19 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-azure-fde-6.2 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-azure-fde-6.8 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-gcp-5.19 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-gcp-6.2 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-gcp-6.5 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-gcp-6.8 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-hwe-5.19 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-hwe-6.2 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-hwe-6.5 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-hwe-6.8 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-ibm-6.8 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-intel-iot-realtime | All versions |
| Ubuntu:22.04:LTS | canonical | linux-intel-iotg | All versions |
| Ubuntu:22.04:LTS | canonical | linux-lowlatency | All versions |
| Ubuntu:22.04:LTS | canonical | linux-lowlatency-hwe-5.19 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-lowlatency-hwe-6.2 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-lowlatency-hwe-6.5 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-lowlatency-hwe-6.8 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-nvidia | All versions |
| Ubuntu:22.04:LTS | canonical | linux-nvidia-6.2 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-nvidia-6.5 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-nvidia-6.8 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-nvidia-tegra | All versions |
| Ubuntu:22.04:LTS | canonical | linux-nvidia-tegra-igx | All versions |
| Ubuntu:22.04:LTS | canonical | linux-oem-5.17 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-oem-6.0 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-oem-6.1 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-oem-6.5 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-oracle-6.5 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-oracle-6.8 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-realtime | All versions |
| Ubuntu:22.04:LTS | canonical | linux-riscv-5.19 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-riscv-6.5 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-riscv-6.8 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-starfive-5.19 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-starfive-6.2 | All versions |
| Ubuntu:22.04:LTS | canonical | linux-starfive-6.5 | All versions |
| Ubuntu:Pro:Realtime:22.04:LTS | canonical | linux-realtime-6.8 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-aws-6.14 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-aws-6.17 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-aws-7.0 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-azure-6.11 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-azure-6.14 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-azure-6.17 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-azure-7.0 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-azure-fde-6.14 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-azure-fde-6.17 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-azure-fde-7.0 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-azure-nvidia | All versions |
| Ubuntu:24.04:LTS | canonical | linux-azure-nvidia-6.14 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-gcp-6.11 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-gcp-6.14 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-gcp-6.17 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-gcp-7.0 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-hwe-6.11 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-hwe-6.14 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-hwe-6.17 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-hwe-7.0 |
< 7.0.0-42.42~24.04.1 Fix: upgrade to 7.0.0-42.42~24.04.1
|
| Ubuntu:24.04:LTS | canonical | linux-lowlatency-hwe-6.11 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-nvidia-6.11 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-nvidia-6.17 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-nvidia-7.0 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-nvidia-lowlatency | All versions |
| Ubuntu:24.04:LTS | canonical | linux-oem-6.11 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-oem-6.14 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-oem-6.17 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-oem-6.8 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-oracle-6.14 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-oracle-6.17 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-oracle-7.0 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-raspi-realtime | All versions |
| Ubuntu:24.04:LTS | canonical | linux-riscv-6.14 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-riscv-6.17 | All versions |
| Ubuntu:24.04:LTS | canonical | linux-riscv-7.0 |
< 7.0.0-42.42.1~24.04.1 Fix: upgrade to 7.0.0-42.42.1~24.04.1
|
| Ubuntu:24.04:LTS | canonical | linux-xilinx | All versions |
| Ubuntu:Pro:Realtime:24.04:LTS | canonical | linux-realtime-6.14 | All versions |
| Ubuntu:Pro:Realtime:24.04:LTS | canonical | linux-realtime-6.17 | All versions |
| Ubuntu:26.04:LTS | canonical | linux-nvidia-bos | All versions |
| Ubuntu:26.04:LTS | canonical | linux-oem-7.0 |
< 7.0.0-1017.17 Fix: upgrade to 7.0.0-1017.17
|
| Linux | linux | kernel |
>= 5.2.0, < 7.2.6 >= 6.19.0, < 7.2.6 Fix: upgrade to 7.2.6
|
| Alpaquita:23 | bellsoft | linux-lts |
>= 6.1.182-r0 >= 6.1.189-r0, < 6.1.191-r0 Fix: upgrade to 6.1.191-r0
|
| Alpaquita:25 | bellsoft | linux-lts |
>= 6.12.103-r0 >= 6.12.112-r0, < 6.12.115-r0 Fix: upgrade to 6.12.115-r0
|
| Alpaquita:stream | bellsoft | linux-lts |
>= 6.18.46-r0 >= 6.18.55-r0, < 6.18.58-r0 Fix: upgrade to 6.18.58-r0
|
| Ubuntu:24.04:LTS | canonical | linux-vmware | All versions |
| – | linux | linux |
< 20b2c2f3316e82a76ae3358c0bd45824f50f3fd5 5.2 < f3e6b504a79d8e90bb7aa8a03a42dc2b51dcc4c4 |
| Ubuntu:26.04:LTS | canonical | linux |
< 7.0.0-42.42 Fix: upgrade to 7.0.0-42.42
|
| Ubuntu:26.04:LTS | canonical | linux-aws |
< 7.0.0-1016.17 Fix: upgrade to 7.0.0-1016.17
|
| Ubuntu:26.04:LTS | canonical | linux-gcp |
< 7.0.0-1016.18 Fix: upgrade to 7.0.0-1016.18
|
| Ubuntu:26.04:LTS | canonical | linux-ibm |
< 7.0.0-1017.17 Fix: upgrade to 7.0.0-1017.17
|
| Ubuntu:26.04:LTS | canonical | linux-oracle |
< 7.0.0-1015.16 Fix: upgrade to 7.0.0-1015.16
|
| Ubuntu:26.04:LTS | canonical | linux-riscv |
< 7.0.0-42.42.1 Fix: upgrade to 7.0.0-42.42.1
|
Original advisory text
BELL-CVE-2026-90263
In the Linux kernel, the following vulnerability has been resolved: btrfs: check if root is readonly when setting posix acl For a filesystem which has btrfs read-only property set to true, all write operations including acl and xattr should be denied. However, acl can still be set even if btrfs ro property is true. This happens because no function on the set_acl code path checks the root is readonly or not. It was checked in btrfs_setxattr_trans() but got removed in commit 353c2ea735e4 ("btrfs: remove redundant readonly root check in btrfs_setxattr_trans") That commit didn't check if all the callers properly check the root's read-only flag. A previous fix is commit b51111271b03 ("btrfs: check if root is readonly while setting security xattr"). Always check if the root is read-only before performing the set acl operation.
References
- https://security-tracker.debian.org/tracker/CVE-2026-90263 Vendor Advisory
- https://docs.bell-sw.com/security/cves/CVE-2026-90263 Vendor Advisory
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90263... Vendor Advisory
- https://git.kernel.org/stable/c/ce8103676f4d4b13e1f087fcfb34f80774d30be2 URL
- https://ubuntu.com/security/CVE-2026-90263 Third Party Advisory
- https://git.kernel.org/stable/c/d5602f96ff1e266f069b4d0d94f441050e057e06 URL
- https://www.cve.org/CVERecord?id=CVE-2026-90263 Third Party Advisory
- https://git.kernel.org/linus/01c2f41fc441f75b3f9326443372faceb1cb6638 Third Party Advisory
- https://git.kernel.org/stable/c/20b2c2f3316e82a76ae3358c0bd45824f50f3fd5 URL
- https://git.kernel.org/stable/c/dc3a6e90a0a6350a6d43fed9f005f54171809580 URL
- https://git.kernel.org/stable/c/01c2f41fc441f75b3f9326443372faceb1cb6638 URL
- https://git.kernel.org/stable/c/f3e6b504a79d8e90bb7aa8a03a42dc2b51dcc4c4 URL
- https://nvd.nist.gov/vuln/detail/CVE-2026-90263 Vendor Advisory
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git Product
- https://ubuntu.com/security/notices/USN-8959-1 Vendor Advisory
- https://ubuntu.com/security/notices/USN-8960-1 Vendor Advisory
Severity
6.3
Medium
Timeline
Published19 Sep 2026
Updated4 Nov 2026
First seen17 Sep 2026
Sources
CVE-2026-90263 · NVD
DEBIAN-CVE-2026-90263 · OSV
UBUNTU-CVE-2026-90263 · OSV
CVE-2026-90263 · OSV
BELL-CVE-2026-90263 · OSV
CVE-2026-90263 · MITRE
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