Linux kernel SELinux disables NFSv4 labeling on second mount
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: 7 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
The Linux kernel SELinux module is affected from 3.11 before the fixed versions listed below. When an NFSv4 filesystem exported with security_label is mounted a second time, the reused superblock skips setting the native labels flag, so the NFS client disables per-file labeling on the shared server for both mounts.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
Description from the CNA
In the Linux kernel, the following vulnerability has been resolved: selinux: preserve NATIVE_LABELS on already-initialized sb in set_mnt_opts When an NFSv4 filesystem exported with security_label is mounted a second time, sget_fc() returns the existing superblock and nfs_get_root() calls security_sb_set_mnt_opts() again on it. Since the superblock is already SB_INITIALIZED, selinux_set_mnt_opts() takes an early exit without setting SECURITY_LSM_NATIVE_LABELS in *set_kern_flags. nfs_get_root() then sees kflags without SECURITY_LSM_NATIVE_LABELS set and clears NFS_CAP_SECURITY_LABEL on the shared nfs_server, silently disabling per-file labeling for both the new and the original mount. Commit 3815a245b501 ("security/selinux: fix SECURITY_LSM_NATIVE_LABELS on reused superblock") fixed the same problem in selinux_sb_clone_mnt_opts(). The reused-superblock path for a plain second mount now goes through sb_set_mnt_opts rather than sb_clone_mnt_opts, so it needs the same treatment: on both SE_SBINITIALIZED early exits, set SECURITY_LSM_NATIVE_LABELS in *set_kern_flags when the superblock was already using SECURITY_FS_USE_NATVE.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 3.11 and later | 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.57, 7.2.11, 7.3 | Patch available | CNA |
- Linux VendorLinux Affected 3.11 and later Fixed in 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.57, 7.2.11, 7.3 Patch available CNA
Remediation
Update to Linux kernel 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.57, 7.2.11 or 7.3, or to a version that includes the fixing commits. Red Hat lists Red Hat Enterprise Linux 6 as affected with no fix planned, and Red Hat Enterprise Linux 7, 8, 9 and 10 and Red Hat OpenShift Container Platform 4 and 5 as affected with no fix available.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
- Fix · CNA Linux (Linux) Fixed in 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.57, 7.2.11, 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 |
| Red Hat Enterprise Linux 7 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Timeline
- 2026-10-23 Threatist record created from CVE-2026-99052
- 2026-10-23 Alias added: GHSA-8mqq-3q6f-v2w5
- 2026-10-27 Affected versions changed · Red Hat
- 2026-10-27 CVSS score added · Red Hat
- 2026-10-30 Fix available: Linux/Linux@22987d24a159ed7df3cdc9090ca5d61e58df0cac, Linux/Linux@2f0f1f5a3b89c1ed67e39be49d29ee7f5c96e039, Linux/[email protected] +3 · CNA
- 2026-10-30 3 new references · CNA
- 2026-11-06 Affected versions changed · Red Hat
References
Other 8
- https://git.kernel.org/stable/c/22987d24a159ed7df3cdc9090ca5d61e58df0cac
- https://git.kernel.org/stable/c/2f0f1f5a3b89c1ed67e39be49d29ee7f5c96e039
- https://git.kernel.org/stable/c/dc579e43b13cb65e55eabaae4f1a950e43567fb1
- https://git.kernel.org/stable/c/a545def625860d4ccedc14fe45e884a62a041cef
- https://git.kernel.org/stable/c/a6da93c625b3557dd23ff6db45d2d1bafeae1565
- https://git.kernel.org/stable/c/5509d498e1b9edafebd5a60ba3cb9ecfda23dc2b
- https://git.kernel.org/stable/c/c997832414f1d846de0a1fa38d7d4f62ba2ea917
- https://git.kernel.org/stable/c/28b7260548af3d35773477993ad4e4de41578dd7
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Sources
- CVE-2026-99052 · CVE Program
- CVE-2026-99052 · NVD
- FIRST EPSS
- GHSA-8mqq-3q6f-v2w5 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-99052 · Red Hat security data · CC BY 4.0
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