btrfs: check if root is readonly when setting posix acl
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
- —
- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 2 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
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.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.1.191, 6.6.160, 6.12.114, 6.18.57, 7.2.6, 7.3
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
Not affected: 5 products
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4
- Red Hat OpenShift Container Platform 5
Timeline
- 2026-10-02 Threatist record created from CVE-2026-90263
- 2026-10-03 Alias added: GHSA-wxw8-hpqh-3xg2
- 2026-10-15 Affected versions changed · Red Hat
- 2026-10-15 CVSS score added · Red Hat
- 2026-10-16 Fix available: Linux/[email protected], Linux/Linux@ce8103676f4d4b13e1f087fcfb34f80774d30be2 · CNA
- 2026-10-16 1 new reference · CNA
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-21 Affected versions changed · Red Hat
- 2026-10-21 CVSS score changed · Red Hat
- 2026-10-21 Fix available: Linux/Linux@20b2c2f3316e82a76ae3358c0bd45824f50f3fd5, Linux/[email protected], Linux/[email protected] +1 · CNA
- 2026-10-21 2 new references · CNA
- 2026-10-30 Fix available: Linux/[email protected], Linux/Linux@f3e6b504a79d8e90bb7aa8a03a42dc2b51dcc4c4 · CNA
- 2026-10-30 1 new reference · CNA
- 2026-11-06 Affected versions changed · Red Hat
References
Other 6
- https://git.kernel.org/stable/c/f3e6b504a79d8e90bb7aa8a03a42dc2b51dcc4c4
- https://git.kernel.org/stable/c/20b2c2f3316e82a76ae3358c0bd45824f50f3fd5
- https://git.kernel.org/stable/c/dc3a6e90a0a6350a6d43fed9f005f54171809580
- https://git.kernel.org/stable/c/ce8103676f4d4b13e1f087fcfb34f80774d30be2
- https://git.kernel.org/stable/c/d5602f96ff1e266f069b4d0d94f441050e057e06
- https://git.kernel.org/stable/c/01c2f41fc441f75b3f9326443372faceb1cb6638
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Sources
- CVE-2026-90263 · CVE Program
- CVE-2026-90263 · NVD
- FIRST EPSS
- GHSA-wxw8-hpqh-3xg2 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-90263 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences