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Fencer Vulns
no cvss —

CVE-2023-54134 json

autofs: fix memory leak of waitqueues in autofs_catatonic_mode

published 2025-12-24 10 mo ago modified 2026-06-17 4 mo ago also EUVD-2023-60311

cvss
—
not scored
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 14%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

autofs: fix memory leak of waitqueues in autofs_catatonic_mode

Syzkaller reports a memory leak:

BUG: memory leak unreferenced object 0xffff88810b279e00 (size 96): comm "syz-executor399", pid 3631, jiffies 4294964921 (age 23.870s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 08 9e 27 0b 81 88 ff ff ..........'..... 08 9e 27 0b 81 88 ff ff 00 00 00 00 00 00 00 00 ..'............. backtrace: [<ffffffff814cfc90>] kmalloc_trace+0x20/0x90 mm/slab_common.c:1046 [<ffffffff81bb75ca>] kmalloc include/linux/slab.h:576 [inline] [<ffffffff81bb75ca>] autofs_wait+0x3fa/0x9a0 fs/autofs/waitq.c:378 [<ffffffff81bb88a7>] autofs_do_expire_multi+0xa7/0x3e0 fs/autofs/expire.c:593 [<ffffffff81bb8c33>] autofs_expire_multi+0x53/0x80 fs/autofs/expire.c:619 [<ffffffff81bb6972>] autofs_root_ioctl_unlocked+0x322/0x3b0 fs/autofs/root.c:897 [<ffffffff81bb6a95>] autofs_root_ioctl+0x25/0x30 fs/autofs/root.c:910 [<ffffffff81602a9c>] vfs_ioctl fs/ioctl.c:51 [inline] [<ffffffff81602a9c>] __do_sys_ioctl fs/ioctl.c:870 [inline] [<ffffffff81602a9c>] __se_sys_ioctl fs/ioctl.c:856 [inline] [<ffffffff81602a9c>] __x64_sys_ioctl+0xfc/0x140 fs/ioctl.c:856 [<ffffffff84608225>] do_syscall_x64 arch/x86/entry/common.c:50 [inline] [<ffffffff84608225>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 [<ffffffff84800087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

autofs_wait_queue structs should be freed if their wait_ctr becomes zero. Otherwise they will be lost.

In this case an AUTOFS_IOC_EXPIRE_MULTI ioctl is done, then a new waitqueue struct is allocated in autofs_wait(), its initial wait_ctr equals 2. After that wait_event_killable() is interrupted (it returns -ERESTARTSYS), so that 'wq->name.name == NULL' condition may be not satisfied. Actually, this condition can be satisfied when autofs_wait_release() or autofs_catatonic_mode() is called and, what is also important, wait_ctr is decremented in those places. Upon the exit of autofs_wait(), wait_ctr is decremented to 1. Then the unmounting process begins: kill_sb calls autofs_catatonic_mode(), which should have freed the waitqueues, but it only decrements its usage counter to zero which is not a correct behaviour.

edit:imk This description is of course not correct. The umount performed as a result of an expire is a umount of a mount that has been automounted, it's not the autofs mount itself. They happen independently, usually after everything mounted within the autofs file system has been expired away. If everything hasn't been expired away the automount daemon can still exit leaving mounts in place. But expires done in both cases will result in a notification that calls autofs_wait_release() with a result status. The problem case is the summary execution of of the automount daemon. In this case any waiting processes won't be woken up until either they are terminated or the mount is umounted. end edit: imk

So in catatonic mode we should free waitqueues which counter becomes zero.

edit: imk Initially I was concerned that the calling of autofs_wait_release() and autofs_catatonic_mode() was not mutually exclusive but that can't be the case (obviously) because the queue entry (or entries) is removed from the list when either of these two functions are called. Consequently the wait entry will be freed by only one of these functions or by the woken process in autofs_wait() depending on the order of the calls. end edit: imk

Patch / fix

  • Linux Linux 4.14.326, 4.19.295, 5.4.257, 5.10.197, 5.15.133, 6.1.55, 6.5.5, 6.6
  • linux Debian 12 6.1.55-1
  • linux Debian 14, Debian 13 6.5.6-1

debian advisories DEBIAN-CVE-2023-54134

  • linux Ubuntu 20.04 LTS 5.4.0-169.187
  • linux Ubuntu 22.04 LTS 5.15.0-94.104
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1116.126
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1053.58
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1120.129
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1051.59
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1050.55
  • linux-ibm Ubuntu 20.04 LTS 5.4.0-1063.68

ubuntu advisories UBUNTU-CVE-2023-54134

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel-rt Linux Micro 6.1, Linux Micro 6.0 6.4.0-40.1
  • kernel-source-rt Linux Micro 6.1, Linux Micro 6.0 6.4.0-40.1
  • kernel-source Linux Micro 6.1, Linux Micro 6.0 6.4.0-39.1
  • kernel-default Linux Micro 6.1, Linux Micro 6.0 6.4.0-39.1
  • kernel-kvmsmall Linux Micro 6.1, Linux Micro 6.0 6.4.0-39.1
  • kernel-default-base Linux Micro 6.1, Linux Micro 6.0 6.4.0-39.1.21.16
  • kernel-64kb SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS, SLE High Performance Computing 15 SP5-ESPOS 5.14.21-150500.55.133.1
  • kernel-syms SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS +1 more 5.14.21-150500.55.133.1

suse advisories SUSE-SU-2026:20845-1SUSE-SU-2026:20876-1SUSE-SU-2026:20477-1SUSE-SU-2026:20498-1SUSE-SU-2026:0473-1SUSE-SU-2026:0317-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2023-54134 updated cvss 5.5

kernel: Linux kernel autofs: Denial of Service due to memory leak in autofs_catatonic_mode

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 10 kernel
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 14% of all scored CVEs (FIRST EPSS, 2026-11-08).

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

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