Skip to content
Fencer Vulns
medium 5.5

CVE-2025-39765 json

ALSA: timer: fix ida_free call while not allocated

published 2025-09-11 13 mo ago modified 2026-11-05 3 d ago also EUVD-2025-28947

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 4%
public exploits
0
none known

Summary

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

ALSA: timer: fix ida_free call while not allocated

In the snd_utimer_create() function, if the kasprintf() function return NULL, snd_utimer_put_id() will be called, finally use ida_free() to free the unallocated id 0.

the syzkaller reported the following information: ------------[ cut here ]------------ ida_free called for id=0 which is not allocated. WARNING: CPU: 1 PID: 1286 at lib/idr.c:592 ida_free+0x1fd/0x2f0 lib/idr.c:592 Modules linked in: CPU: 1 UID: 0 PID: 1286 Comm: syz-executor164 Not tainted 6.15.8 #3 PREEMPT(lazy) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-4.fc42 04/01/2014 RIP: 0010:ida_free+0x1fd/0x2f0 lib/idr.c:592 Code: f8 fc 41 83 fc 3e 76 69 e8 70 b2 f8 (...) RSP: 0018:ffffc900007f79c8 EFLAGS: 00010282 RAX: 0000000000000000 RBX: 1ffff920000fef3b RCX: ffffffff872176a5 RDX: ffff88800369d200 RSI: 0000000000000000 RDI: ffff88800369d200 RBP: 0000000000000000 R08: ffffffff87ba60a5 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000002 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f6f1abc1740(0000) GS:ffff8880d76a0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6f1ad7a784 CR3: 000000007a6e2000 CR4: 00000000000006f0 Call Trace: <TASK> snd_utimer_put_id sound/core/timer.c:2043 [inline] [snd_timer] snd_utimer_create+0x59b/0x6a0 sound/core/timer.c:2184 [snd_timer] snd_utimer_ioctl_create sound/core/timer.c:2202 [inline] [snd_timer] __snd_timer_user_ioctl.isra.0+0x724/0x1340 sound/core/timer.c:2287 [snd_timer] snd_timer_user_ioctl+0x75/0xc0 sound/core/timer.c:2298 [snd_timer] vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl fs/ioctl.c:893 [inline] __x64_sys_ioctl+0x198/0x200 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x7b/0x160 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x76/0x7e [...]

The utimer->id should be set properly before the kasprintf() function, ensures the snd_utimer_put_id() function will free the allocated id.

Patch / fix

  • Linux Linux 6.12.44, 6.16.4, 6.17
  • linux Debian 13 6.12.48-1
  • linux Debian 14 6.16.5-1

debian advisories DEBIAN-CVE-2025-39765

  • kernel-rt Linux Micro 6.2 6.12.0-160000.6.1
  • kernel-64kb SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.6.1
  • kernel-source SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.6.1
  • kernel-default SLES 16.0, SLE High Availability Extension 16.0, Linux Micro 6.2 +1 more 6.12.0-160000.6.1
  • kernel-default-base SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.6.1.160000.2.4
  • kernel-syms SLES 16.0, Linux Micro Extras 6.2, SLES for SAP applications 16.0 6.12.0-160000.6.1
  • kernel-obs-qa SLES for SAP applications 16.0, SLES 16.0 6.12.0-160000.6.1
  • kernel-kvmsmall SLES for SAP applications 16.0, SLES 16.0 6.12.0-160000.6.1

suse advisories SUSE-SU-2025:21074-1SUSE-SU-2025:21139-1SUSE-SU-2026:20560-1SUSE-SU-2025:21179-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.6.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-kvmsmall openSUSE Leap 16.0 6.12.0-160000.6.1

opensuse advisories openSUSE-SU-2025:20081-1

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-2025-39765 updated cvss 5.5

kernel: ALSA: timer: fix ida_free call while not allocated

  • Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernel
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more
    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

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
3 d ago

Exploit prediction

0.16% chance of exploitation in the next 30 days, higher than 4% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

Classification

Weakness
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.