Vulnerability in Kernel (CVE-2025-39796)

Summary

Vulnerability in Kernel (CVE-2025-39796). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 6.15.11, 6.16.2 or later.

Original description

The description as published by the source.

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

net: lapbether: ignore ops-locked netdevs

Syzkaller managed to trigger lock dependency in xsk_notify via
register_netdevice. As discussed in [0], using register_netdevice
in the notifiers is problematic so skip adding lapbeth for ops-locked
devices.

   xsk_notifier+0xa4/0x280 net/xdp/xsk.c:1645
   notifier_call_chain+0xbc/0x410 kernel/notifier.c:85
   call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:2230
   call_netdevice_notifiers_extack net/core/dev.c:2268 [inline]
   call_netdevice_notifiers net/core/dev.c:2282 [inline]
   unregister_netdevice_many_notify+0xf9d/0x2700 net/core/dev.c:12077
   unregister_netdevice_many net/core/dev.c:12140 [inline]
   unregister_netdevice_queue+0x305/0x3f0 net/core/dev.c:11984
   register_netdevice+0x18f1/0x2270 net/core/dev.c:11149
   lapbeth_new_device drivers/net/wan/lapbether.c:420 [inline]
   lapbeth_device_event+0x5b1/0xbe0 drivers/net/wan/lapbether.c:462
   notifier_call_chain+0xbc/0x410 kernel/notifier.c:85
   call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:2230
   call_netdevice_notifiers_extack net/core/dev.c:2268 [inline]
   call_netdevice_notifiers net/core/dev.c:2282 [inline]
   __dev_notify_flags+0x12c/0x2e0 net/core/dev.c:9497
   netif_change_flags+0x108/0x160 net/core/dev.c:9526
   dev_change_flags+0xba/0x250 net/core/dev_api.c:68
   devinet_ioctl+0x11d5/0x1f50 net/i…

Source: OSV.dev (Open Source Vulnerabilities) NVD OSV

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-2025-39796 has been found in Kernel.
Risk of unauthorized operations or information disclosure.
What to do: upgrade Kernel to 6.15.11, 6.16.2 or later.
If unsure, ask your IT team or search "Kernel CVE-2025-39796" on the vendor's site.

CVE-2025-39796 (Kernel)
Patched: 6.15.11, 6.16.2 — 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.

❓ What is the problem

A vulnerability (unclassified) exists in Kernel.

📍 Affected scope

Check the vendor advisory for the affected versions of Kernel.

🔥 Severity

Severity: ?. Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 6.15.11, 6.16.2.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

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

1
Identify 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。
2
Apply patch patch
```
Upgrade Kernel to 6.15.11, 6.16.2
```
ステージング環境で 6.15.11, 6.16.2 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。
3
Post-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

Linux Kernel

[{"type":"ECOSYSTEM","events":[{"introduced":"6.15.0"},{"fixed":"6.15.11"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.16.0"},{"fixed":"6.16.2"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

BellSoft Alpaquita BELL-CVE-2025-39796 linux-lts Fixed in: 6.18.35-r1
Debian DEBIAN-CVE-2025-39796 linux Fixed in: 6.16.3-1
Ubuntu UBUNTU-CVE-2025-39796 linux-hwe-edge