Vulnerability in Kernel (CVE-2025-39765)
Summary
Vulnerability in Kernel (CVE-2025-39765). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 6.12.44, 6.16.4 or later.
Original description
The description as published by the source.
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:
snd_utimer_put_id sound/core/timer.c:2043 [inline] [snd_timer]
snd_utimer_create+0x59b/0x6a0…
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2025-39765 has been found in Kernel.
Risk of unauthorized operations or information disclosure.
What to do: upgrade Kernel to 6.12.44, 6.16.4 or later.
If unsure, ask your IT team or search "Kernel CVE-2025-39765" on the vendor's site.
CVE-2025-39765 (Kernel)
Patched: 6.12.44, 6.16.4 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (unclassified) exists in Kernel.
Check the vendor advisory for the affected versions of Kernel.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 6.12.44, 6.16.4.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'Kernel' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'Kernel' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
Kernelを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade Kernel to 6.12.44, 6.16.4ステージング環境で 6.12.44, 6.16.4 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- BellSoft Alpaquita BELL-CVE-2025-39765 linux-lts Fixed in: 6.12.44-r0
- Debian DEBIAN-CVE-2025-39765 linux Fixed in: 6.12.48-1
- Ubuntu UBUNTU-CVE-2025-39765 linux-hwe-edge
References
- advisory github.com
- advisory nvd.nist.gov
- package git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org