What is CVE-2025-39833?

CVE-2025-39833 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10, affecting Linux kernel versions from 2.6.29 onward and patched in 6.16.5 and 6.17. CVE-2025-39833 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2025-39833?

CVE-2025-39833 has a CVSS score of 5.5 out of 10, rated Medium severity. The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

Is there a patch available for CVE-2025-39833?

Yes, CVE-2025-39833 has been patched. Fixed versions include 6.16.5 and 6.17. If you are running Linux kernel 2.6.29 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2025-39833 actively exploited?

CVE-2025-39833 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2025-39833

Medium

In the Linux kernel, the following vulnerability has been resolved: mISDN: hfcpci: Fix warning when deleting uninitialized timer With CONFIG_DEBUG_OBJECTS_TIMERS unloading hfcpci module leads to the following splat: [ 250.215892] ODEBUG: assert_init not available (active state 0) object: ffffffffc01a3dc0 object type: timer_list hint: 0x0 [ 250.217520] WARNING: CPU: 0 PID: 233 at lib/debugobjects.c:612 debug_print_object+0x1b6/0x2c0 [ 250.218775] Modules linked in: hfcpci(-) mISDN_core [ 250.219537] CPU: 0 UID: 0 PID: 233 Comm: rmmod Not tainted 6.17.0-rc2-g6f713187ac98 #2 PREEMPT(voluntary) [ 250.220940] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 250.222377] RIP: 0010:debug_print_object+0x1b6/0x2c0 [ 250.223131] Code: fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 4f 41 56 48 8b 14 dd a0 4e 01 9f 48 89 ee 48 c7 c7 20 46 01 9f e8 cb 84d [ 250.225805] RSP: 0018:ffff888015ea7c08 EFLAGS: 00010286 [ 250.226608] RAX: 0000000000000000 RBX: 0000000000000005 RCX: ffffffff9be93a95 [ 250.227708] RDX: 1ffff1100d945138 RSI: 0000000000000008 RDI: ffff88806ca289c0 [ 250.228993] RBP: ffffffff9f014a00 R08: 0000000000000001 R09: ffffed1002bd4f39 [ 250.230043] R10: ffff888015ea79cf R11: 0000000000000001 R12: 0000000000000001 [ 250.231185] R13: ffffffff9eea0520 R14: 0000000000000000 R15: ffff888015ea7cc8 [ 250.232454] FS: 00007f3208f01540(0000) GS:ffff8880caf5a000(0000) knlGS:0000000000000000 [ 250.233851] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 250.234856] CR2: 00007f32090a7421 CR3: 0000000004d63000 CR4: 00000000000006f0 [ 250.236117] Call Trace: [ 250.236599] <TASK> [ 250.236967] ? trace_irq_enable.constprop.0+0xd4/0x130 [ 250.237920] debug_object_assert_init+0x1f6/0x310 [ 250.238762] ? __pfx_debug_object_assert_init+0x10/0x10 [ 250.239658] ? __lock_acquire+0xdea/0x1c70 [ 250.240369] __try_to_del_timer_sync+0x69/0x140 [ 250.241172] ? __pfx___try_to_del_timer_sync+0x10/0x10 [ 250.242058] ? __timer_delete_sync+0xc6/0x120 [ 250.242842] ? lock_acquire+0x30/0x80 [ 250.243474] ? __timer_delete_sync+0xc6/0x120 [ 250.244262] __timer_delete_sync+0x98/0x120 [ 250.245015] HFC_cleanup+0x10/0x20 [hfcpci] [ 250.245704] __do_sys_delete_module+0x348/0x510 [ 250.246461] ? __pfx___do_sys_delete_module+0x10/0x10 [ 250.247338] do_syscall_64+0xc1/0x360 [ 250.247924] entry_SYSCALL_64_after_hwframe+0x77/0x7f Fix this by initializing hfc_tl timer with DEFINE_TIMER macro. Also, use mod_timer instead of manual timeout update.

Package Linux Kernel

Published 2025-09-16

Last modified 2026-01-14

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

5.5

out of 10

Medium

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

High

Vector string

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness type

CWE-908

CVE-2025-39833 is classified as CWE-908

See CWE-908 on MITRE CWE for full details on this weakness type.

Affected versions

Linux kernel versions 2.6.29 and later are affected. Fixed in 6.16.5, 6.17 and their respective stable series.

Affected from

≥ 2.6.29

Fixed in

✓ 6.16.5 6.16.x ✓ 6.17

References

The following references provide additional information about CVE-2025-39833 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

Kernel patch commit
https://git.kernel.org/stable/c/43fc5da8133badf17f5df250ba03b9d882254845
Patch
Kernel patch commit
https://git.kernel.org/stable/c/97766512a9951b9fd6fc97f1b93211642bb0b220
Patch

Details

CVE ID CVE-2025-39833

Severity Medium

CVSS score 5.5 / 10

CVSS version 3.1

Published 2025-09-16

Modified 2026-01-14

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2025-39833?

CVE-2025-39833 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 . It affects Linux kernel versions from 2.6.29 onward and has been patched in 6.16.5 and 6.17. CVE-2025-39833 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2025-39833?

CVE-2025-39833 has a CVSS score of 5.5 out of 10, rated Medium severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
Is there a patch available for CVE-2025-39833?

Yes — CVE-2025-39833 has been patched. Fixed versions include 6.16.5 and 6.17. If you are running Linux kernel 2.6.29 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2025-39833 actively exploited?

No — CVE-2025-39833 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.