Vulnerability in Kernel (CVE-2025-39818)

Summary

Vulnerability in Kernel (CVE-2025-39818). Successful exploitation can lead to full system takeover. Mitigation: upgrade to 6.16.5 or later.

Original description

The description as published by the source.

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

HID: intel-thc-hid: intel-thc: Fix incorrect pointer arithmetic in I2C regs save

Improper use of secondary pointer (&dev->i2c_subip_regs) caused
kernel crash and out-of-bounds error:

BUG: KASAN: slab-out-of-bounds in _regmap_bulk_read+0x449/0x510
Write of size 4 at addr ffff888136005dc0 by task kworker/u33:5/5107

CPU: 3 UID: 0 PID: 5107 Comm: kworker/u33:5 Not tainted 6.16.0+ #3 PREEMPT(voluntary)
Workqueue: async async_run_entry_fn
Call Trace:

dump_stack_lvl+0x76/0xa0
print_report+0xd1/0x660
? __pfx__raw_spin_lock_irqsave+0x10/0x10
? kasan_complete_mode_report_info+0x26/0x200
kasan_report+0xe1/0x120
? _regmap_bulk_read+0x449/0x510
? _regmap_bulk_read+0x449/0x510
__asan_report_store4_noabort+0x17/0x30
_regmap_bulk_read+0x449/0x510
? __pfx__regmap_bulk_read+0x10/0x10
regmap_bulk_read+0x270/0x3d0
pio_complete+0x1ee/0x2c0 [intel_thc]
? __pfx_pio_complete+0x10/0x10 [intel_thc]
? __pfx_pio_wait+0x10/0x10 [intel_thc]
? regmap_update_bits_base+0x13b/0x1f0
thc_i2c_subip_pio_read+0x117/0x270 [intel_thc]
thc_i2c_subip_regs_save+0xc2/0x140 [intel_thc]
? __pfx_thc_i2c_subip_regs_save+0x10/0x10 [intel_thc]
[...]
The buggy address belongs to the object at ffff888136005d00
which belongs to the cache kmalloc-rnd-12-192 of size 192
The buggy address is located 0 bytes to the right of
allocated 192-byte region [ffff888136005d00, ffff888136005dc0)

Replaced with direct array…

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-2025-39818 has been found in Kernel.
Successful exploitation can lead to full system takeover.
What to do: upgrade Kernel to 6.16.5 or later.
If unsure, ask your IT team or search "Kernel CVE-2025-39818" on the vendor's site.

CVE-2025-39818 (Kernel)
Attack vector: local / no user interaction
Patched: 6.16.5 — 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: ?. Successful exploitation can lead to full system takeover.

🔧 How to fix

Update to 6.16.5.

🛡️ 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 6.16.5
```
ステージング環境で 6.16.5 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":"6.14.0"},{"fixed":"6.16.5"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

BellSoft Alpaquita BELL-CVE-2025-39818 linux-lts Fixed in: 6.18.35-r1
Debian DEBIAN-CVE-2025-39818 linux Fixed in: 6.16.5-1
Ubuntu UBUNTU-CVE-2025-39818 linux-hwe-edge