CVE-2026-78409
ADVISORY - nistSummary
The X-mount.subdir option uses a detached-tree fast path on Linux 6.15 and later and passes the configured subdirectory to open_tree() with AT_SYMLINK_NOFOLLOW. That flag does not stop intermediate symlink traversal or keep resolution inside the newly mounted filesystem. A local unprivileged user with an fstab-authorized X-mount.subdir entry can attach a host path at the intended mountpoint.
EPSS Score: 0.00154 (0.040)
Common Weakness Enumeration (CWE)
ADVISORY - nist
Improper Link Resolution Before File Access ('Link Following')
ADVISORY - redhat
Improper Link Resolution Before File Access ('Link Following')
Alpine
CREATED
UPDATED
ADVISORY IDCVE-2026-78409
EXPLOITABILITY SCORE
-
EXPLOITS FOUND
-
COMMON WEAKNESS ENUMERATION (CWE)-
| Package | Type | OS Name | OS Version | Affected Ranges | Fix Versions |
|---|---|---|---|---|---|
| alpine/util-linux | apk | alpine | 3.24 | <2.42.3-r0 | 2.42.3-r0 |
| alpine/util-linux | apk | alpine | edge | <2.42.3-r0 | 2.42.3-r0 |
Severity and metrics
No CVSS data available from this advisory.
NIST
CREATED
UPDATED
ADVISORY IDCVE-2026-78409
EXPLOITABILITY SCORE
1
EXPLOITS FOUND
-
COMMON WEAKNESS ENUMERATION (CWE)
CVSS SCORE
7highDebian
CREATED
UPDATED
ADVISORY IDCVE-2026-78409
EXPLOITABILITY SCORE
-
EXPLOITS FOUND
-
COMMON WEAKNESS ENUMERATION (CWE)-
Ubuntu
CREATED
UPDATED
ADVISORY IDCVE-2026-78409
EXPLOITABILITY SCORE
-
EXPLOITS FOUND
-
COMMON WEAKNESS ENUMERATION (CWE)-
CVSS SCORE
N/AmediumRed Hat
CREATED
UPDATED
ADVISORY IDCVE-2026-78409
EXPLOITABILITY SCORE
1.0
EXPLOITS FOUND
-
COMMON WEAKNESS ENUMERATION (CWE)