Busybox: busybox: non-root mount option filter bypass allows clearing fstab security restrictions
Summary
| CVE | CVE-2026-88838 |
|---|---|
| State | PUBLISHED |
| Assigner | redhat |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-10-13 17:17:48 UTC |
| Updated | 2026-10-15 16:33:26 UTC |
| Description | A flaw was found in BusyBox's mount utility. A non-root user can bypass mount security restrictions set in /etc/fstab by specifying clearing-mask options on the command line. These options pass the non-root flag filter and are merged with fstab options as strings; when the combined options are re-parsed, clearing options can override nosuid, nodev, and noexec protections the administrator intended to enforce. |
Risk And Classification
Primary CVSS: v3.1 5.5 MEDIUM from [email protected]
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
EPSS: 0.001130000 probability, percentile 0.013380000 (date 2026-10-14)
Problem Types: CWE-693 | CWE-693 Protection Mechanism Failure
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 5.5 | MEDIUM | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N |
| 3.1 | CNA | CVSS | 5.5 | MEDIUM | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N |
CVSS v3.1 Breakdown
Attack Vector
LocalAttack Complexity
LowPrivileges Required
LowUser Interaction
NoneScope
UnchangedConfidentiality
NoneIntegrity
HighAvailability
NoneCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Red Hat | Red Hat Hardened Images | Not specified | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| bugzilla.redhat.com/show_bug.cgi | [email protected] | bugzilla.redhat.com | |
| access.redhat.com/security/cve/CVE-2026-88838 | [email protected] | access.redhat.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Red Hat would like to thank Shubham Raj (Causal Security) for reporting this issue. (en)
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| CNA | 2026-09-09T00:00:00.000Z | Reported to Red Hat. |
| CNA | 2026-10-13T13:50:19.705Z | Made public. |
Workarounds
CNA: Do not install BusyBox mount setuid root where user-mountable fstab entries use nosuid, nodev, or noexec. Remove user/users from sensitive fstab lines, or use util-linux mount.
There are currently no legacy QID mappings associated with this CVE.