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CVE-2026-78409

CVE-2026-78409 · Util-linux: util-linux: x-mount.subdir detached-tree resolution can escape via intermediate symlinks

This page contains facts from public vulnerability sources. Check the original advisory before updating.

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 7.0 · High · EPSS 0.2% · Fix available

Published
Updated

Stack: system

Affected products and versions

  • red hat hardened images

    Versions
    • ≥ 2.42.2-3.4.hum1: Not affected (rpm)

    No fix published

  • red hat enterprise linux 10

    No fix published

  • red hat enterprise linux 7

    No fix published

  • red hat enterprise linux 8

    No fix published

  • red hat enterprise linux 9

    No fix published

  • red hat openshift container platform 4

    No fix published

  • util-linux Debian:12

    Versions
    • 2.38.1-5
    • 2.38.1-5+deb12u1
    • 2.38.1-5+deb12u2
    • 2.38.1-5+deb12u3
    • 2.38.1-5+loong64
    • 2.38.1-6
    • 2.39.1-1
    • 2.39.1-2
    • 2.39.1-3
    • 2.39.1-4
    • 2.39.2-1
    • 2.39.2-2
    • 2.39.2-2.1
    • 2.39.2-2.2
    • 2.39.2-3
    • 2.39.2-4
    • 2.39.2-5
    • 2.39.2-6
    • 2.39.3-1
    • 2.39.3-10
    • 2.39.3-11
    • 2.39.3-2
    • 2.39.3-3
    • 2.39.3-4
    • 2.39.3-5
    • 2.39.3-6
    • 2.39.3-6.1
    • 2.39.3-6.1~exp1
    • 2.39.3-7
    • 2.39.3-8
    • 2.39.3-9
    • 2.40-1
    • 2.40-2
    • 2.40-3
    • 2.40-4
    • 2.40-5
    • 2.40-6
    • 2.40-7
    • 2.40-8
    • 2.40.1-1
    • 2.40.1-2
    • 2.40.1-3
    • 2.40.1-4
    • 2.40.1-4+hurd.1
    • 2.40.1-6
    • 2.40.1-7
    • 2.40.1-8
    • 2.40.1-8.1
    • 2.40.1-9
    • 2.40.2-1
    • 2.40.2-10
    • 2.40.2-11
    • 2.40.2-12
    • 2.40.2-12+hurd.1
    • 2.40.2-13
    • 2.40.2-14
    • 2.40.2-2
    • 2.40.2-3
    • 2.40.2-4
    • 2.40.2-5
    • 2.40.2-6
    • 2.40.2-7
    • 2.40.2-8
    • 2.40.2-9
    • 2.40.3-1
    • 2.40.4-1
    • 2.40.4-2
    • 2.40.4-3
    • 2.40.4-4
    • 2.40.4-5
    • 2.40~rc2-1
    • 2.40~rc2-2
    • 2.40~rc2-3
    • 2.40~rc2-4
    • 2.40~rc2-5
    • 2.40~rc2-6
    • 2.40~rc2-7
    • 2.40~rc2-8
    • 2.41-1
    • 2.41-2
    • 2.41-3
    • 2.41-4
    • 2.41-5
    • 2.41.1-1
    • 2.41.1-2
    • 2.41.1-3
    • 2.41.1-4
    • 2.41.2-1
    • 2.41.2-2
    • 2.41.2-3
    • 2.41.2-4
    • 2.41.3-1
    • 2.41.3-2
    • 2.41.3-3
    • 2.41.3-4
    • 2.41~rc1-1
    • 2.41~rc1-2
    • 2.41~rc2-1
    • 2.42-1
    • 2.42-2
    • 2.42-3
    • 2.42-4
    • 2.42-5
    • 2.42-6
    • 2.42.1-1
    • 2.42.1-2
    • 2.42.1-3
    • 2.42.1-4
    • 2.42.1-5
    • 2.42.1-6
    • 2.42.2-1
    • 2.42.2-2
    • 2.42.2-3
    • 2.42.2-4
    • 2.42.3-1
    • 2.42.4-1
    • 2.42~rc1-1
    • 2.42~rc1-2
    • 2.42~rc1-3
    • 2.42~rc2-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • util-linux Debian:13

    Versions
    • 2.41-5
    • 2.41.1-1
    • 2.41.1-2
    • 2.41.1-3
    • 2.41.1-4
    • 2.41.2-1
    • 2.41.2-2
    • 2.41.2-3
    • 2.41.2-4
    • 2.41.3-1
    • 2.41.3-2
    • 2.41.3-3
    • 2.41.3-4
    • 2.41.5-0+deb13u1
    • 2.42-1
    • 2.42-2
    • 2.42-3
    • 2.42-4
    • 2.42-5
    • 2.42-6
    • 2.42.1-1
    • 2.42.1-2
    • 2.42.1-3
    • 2.42.1-4
    • 2.42.1-5
    • 2.42.1-6
    • 2.42.2-1
    • 2.42.2-2
    • 2.42.2-3
    • 2.42.2-4
    • 2.42.3-1
    • 2.42.4-1
    • 2.42~rc1-1
    • 2.42~rc1-2
    • 2.42~rc1-3
    • 2.42~rc2-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • util-linux Debian:14

    Versions
    • 2.41-5
    • 2.41.1-1
    • 2.41.1-2
    • 2.41.1-3
    • 2.41.1-4
    • 2.41.2-1
    • 2.41.2-2
    • 2.41.2-3
    • 2.41.2-4
    • 2.41.3-1
    • 2.41.3-2
    • 2.41.3-3
    • 2.41.3-4
    • 2.42-1
    • 2.42-2
    • 2.42-3
    • 2.42-4
    • 2.42-5
    • 2.42-6
    • 2.42.1-1
    • 2.42.1-2
    • 2.42.1-3
    • 2.42.1-4
    • 2.42.1-5
    • 2.42.1-6
    • 2.42.2-1
    • 2.42.2-2
    • 2.42.2-3
    • 2.42.2-4
    • 2.42~rc1-1
    • 2.42~rc1-2
    • 2.42~rc1-3
    • 2.42~rc2-1
    Affected ranges
    • ECOSYSTEM: < 2.42.3-1

    Update to 2.42.3-1

  • util-linux Ubuntu:14.04:LTS

    Versions
    • 2.20.1-5.1ubuntu9
    • 2.20.1-5.1ubuntu10
    • 2.20.1-5.1ubuntu11
    • 2.20.1-5.1ubuntu12
    • 2.20.1-5.1ubuntu13
    • 2.20.1-5.1ubuntu14
    • 2.20.1-5.1ubuntu15
    • 2.20.1-5.1ubuntu16
    • 2.20.1-5.1ubuntu17
    • 2.20.1-5.1ubuntu18
    • 2.20.1-5.1ubuntu19
    • 2.20.1-5.1ubuntu20
    • 2.20.1-5.1ubuntu20.1
    • 2.20.1-5.1ubuntu20.2
    • 2.20.1-5.1ubuntu20.3
    • 2.20.1-5.1ubuntu20.4
    • 2.20.1-5.1ubuntu20.6
    • 2.20.1-5.1ubuntu20.7
    • 2.20.1-5.1ubuntu20.9
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • util-linux Ubuntu:Pro:16.04:LTS

    Versions
    • 2.26.2-6ubuntu3
    • 2.27-3ubuntu1
    • 2.27.1-1ubuntu2
    • 2.27.1-1ubuntu3
    • 2.27.1-1ubuntu4
    • 2.27.1-3ubuntu1
    • 2.27.1-4ubuntu1
    • 2.27.1-6ubuntu1
    • 2.27.1-6ubuntu2
    • 2.27.1-6ubuntu3
    • 2.27.1-6ubuntu3.1
    • 2.27.1-6ubuntu3.2
    • 2.27.1-6ubuntu3.3
    • 2.27.1-6ubuntu3.4
    • 2.27.1-6ubuntu3.6
    • 2.27.1-6ubuntu3.7
    • 2.27.1-6ubuntu3.8
    • 2.27.1-6ubuntu3.9
    • 2.27.1-6ubuntu3.10
    • 2.27.1-6ubuntu3.10+esm2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • util-linux Ubuntu:18.04:LTS

    Versions
    • 2.30.1-0ubuntu4
    • 2.30.2-0.1ubuntu1
    • 2.30.2-0.1ubuntu2
    • 2.30.2-0.1ubuntu3
    • 2.31.1-0.4ubuntu2
    • 2.31.1-0.4ubuntu3
    • 2.31.1-0.4ubuntu3.1
    • 2.31.1-0.4ubuntu3.2
    • 2.31.1-0.4ubuntu3.3
    • 2.31.1-0.4ubuntu3.4
    • 2.31.1-0.4ubuntu3.5
    • 2.31.1-0.4ubuntu3.6
    • 2.31.1-0.4ubuntu3.7
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • util-linux Ubuntu:Pro:20.04:LTS

    Versions
    • 2.34-0.1ubuntu2
    • 2.34-0.1ubuntu4
    • 2.34-0.1ubuntu5
    • 2.34-0.1ubuntu6
    • 2.34-0.1ubuntu7
    • 2.34-0.1ubuntu8
    • 2.34-0.1ubuntu9
    • 2.34-0.1ubuntu9.1
    • 2.34-0.1ubuntu9.3
    • 2.34-0.1ubuntu9.4
    • 2.34-0.1ubuntu9.5
    • 2.34-0.1ubuntu9.6
    • 2.34-0.1ubuntu9.6+esm1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • util-linux Ubuntu:22.04:LTS

    Versions
    • 2.36.1-8ubuntu1
    • 2.37.2-4ubuntu1
    • 2.37.2-4ubuntu2
    • 2.37.2-4ubuntu3
    • 2.37.2-4ubuntu3.3
    • 2.37.2-4ubuntu3.4
    • 2.37.2-4ubuntu3.5
    • 2.37.2-4ubuntu3.6
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • util-linux Ubuntu:24.04:LTS

    Versions
    • 2.39.1-4ubuntu2
    • 2.39.2-6ubuntu1
    • 2.39.3-6ubuntu2
    • 2.39.3-9ubuntu2
    • 2.39.3-9ubuntu4
    • 2.39.3-9ubuntu6
    • 2.39.3-9ubuntu6.1
    • 2.39.3-9ubuntu6.2
    • 2.39.3-9ubuntu6.3
    • 2.39.3-9ubuntu6.4
    • 2.39.3-9ubuntu6.5
    • 2.39.3-9ubuntu6.6
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • util-linux Ubuntu:26.10

    Versions
    • 2.41.3-3ubuntu2
    • 2.42.2-1ubuntu2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • util-linux Ubuntu:26.04:LTS

    Versions
    • 2.41-4ubuntu4
    • 2.41.2-4ubuntu1
    • 2.41.2-4ubuntu2
    • 2.41.2-4ubuntu3
    • 2.41.3-3ubuntu1
    • 2.41.3-3ubuntu2
    • 2.41.3-3ubuntu2.2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

Original sources

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