CVE-2026-99052

Security-label loss via reused-superblock flag omission

Published Oct 23, 2026 · Updated Oct 23, 2026

Label loss in Linux SELinux allows local users to disable NFSv4 per-file security labeling by mounting the same export twice. In selinux_set_mnt_opts(), early exits for an initialized superblock omit SECURITY_LSM_NATIVE_LABELS, causing nfs_get_root() to clear NFS_CAP_SECURITY_LABEL on the shared client state. The condition requires SELinux native labeling, a security_label export, and the ability to mount it again; labeling is disabled on both mounts, without an established arbitrary-code execution consequence.

CVSS severityUnavailable
Unscored
EPSS probability0.18%
Next 30 days · Nov 1, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Label loss in Linux SELinux allows local users to disable NFSv4 per-file security labeling by mounting the same export twice. In selinux_set_mnt_opts(), early exits for an initialized superblock omit SECURITY_LSM_NATIVE_LABELS, causing nfs_get_root() to clear NFS_CAP_SECURITY_LABEL on the shared client state. The condition requires SELinux native labeling, a security_label export, and the ability to mount it again; labeling is disabled on both mounts, without an established arbitrary-code execution consequence.

The record

CVE
CVE-2026-99052
Published
Oct 23, 2026
Updated
Oct 23, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Oct 23, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 23, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=3.11
  2. Affected versionversion=eb9ae686507bc5a5ca78e6b3fbe629cd5cc67864 <28b7260548af3d35773477993ad4e4de41578dd7
  3. Affected versionversion=eb9ae686507bc5a5ca78e6b3fbe629cd5cc67864 <5509d498e1b9edafebd5a60ba3cb9ecfda23dc2b
  4. Affected versionversion=eb9ae686507bc5a5ca78e6b3fbe629cd5cc67864 <a545def625860d4ccedc14fe45e884a62a041cef
  5. Affected versionversion=eb9ae686507bc5a5ca78e6b3fbe629cd5cc67864 <a6da93c625b3557dd23ff6db45d2d1bafeae1565
  6. Affected versionversion=eb9ae686507bc5a5ca78e6b3fbe629cd5cc67864 <c997832414f1d846de0a1fa38d7d4f62ba2ea917

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=3.11; version=eb9ae686507bc5a5ca78e6b3fbe629cd5cc67864 <28b7260548af3d35773477993ad4e4de41578dd7; version=eb9ae686507bc5a5ca78e6b3fbe629cd5cc67864 <5509d498e1b9edafebd5a60ba3cb9ecfda23dc2b; version=eb9ae686507bc5a5ca78e6b3fbe629cd5cc67864 <a545def625860d4ccedc14fe45e884a62a041cef; version=eb9ae686507bc5a5ca78e6b3fbe629cd5cc67864 <a6da93c625b3557dd23ff6db45d2d1bafeae1565; version=eb9ae686507bc5a5ca78e6b3fbe629cd5cc67864 <c997832414f1d846de0a1fa38d7d4f62ba2ea917

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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