7.0
High
CVE-2026-78409 Util-linux: util-linux: x-mount.subdir detached-tree resolution can escape via intermediate symlinks
Description
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.
CVSS 3.1 detail
Vector CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:HExploitable with local access to the machine, with an ordinary account and without any user action; an attacker can seriously compromise confidentiality, integrity or availability.
- Attack vector
- Local
- Attack complexity
- High
- Privileges required
- Low
- Interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Affected products and versions
| Product | Affected versions | Fixed in |
|---|---|---|
| Red Hat Enterprise Linux 10 | Versions not published | |
| Red Hat Enterprise Linux 7 | Versions not published | |
| Red Hat Enterprise Linux 8 | Versions not published | |
| Red Hat Enterprise Linux 9 | Versions not published | |
| Red Hat Hardened Images 2.42 | earliest → < 2.42.2-3.4.hum1 | 2.42.2-3.4.hum1 |
| Red Hat OpenShift Container Platform 4 | Versions not published | |
| Red Hat OpenShift Container Platform 5 | Versions not published |
Other CVEs of Red Hat Enterprise Linux 10
The 1455 CVEs of Red Hat Enterprise Linux 10 →
CVE-2026-123876
Podman: containers-common: containers-common: default seccomp af_vsock/netlink_audit deny rules bypassable via 32-bit truncation
4.4
Medium
CVE-2026-120749
Dbus: dbus-daemon: dbus-daemon aborts (reply_serial != 0) when a broadcast from the driver cannot be delivered to a monitored bus
6.2
Medium
CVE-2026-123151
Gdb: gdb: stack buffer overflow in parse_tsv_definition via stale rs->buf tail
Not rated
CVE-2026-121997
Gdb: gdbserver: heap buffer overflow in cmd_qtdpsrc via qtdpsrc declared/actual length mismatch
8.1
High