Vulnerability in Kernel (CVE-2025-21742)

Summary

Vulnerability in Kernel (CVE-2025-21742). Confidential information can be exposed externally. Exploitable via wNdpIndex. Mitigation: upgrade to 6.6.78, 6.12.14, 6.13.3 or later.

Original description

The description as published by the source.

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

usbnet: ipheth: use static NDP16 location in URB

Original code allowed for the start of NDP16 to be anywhere within the
URB based on the wNdpIndex value in NTH16. Only the start position of
NDP16 was checked, so it was possible for even the fixed-length part
of NDP16 to extend past the end of URB, leading to an out-of-bounds
read.

On iOS devices, the NDP16 header always directly follows NTH16. Rely on
and check for this specific format.

This, along with NCM-specific minimal URB length check that already
exists, will ensure that the fixed-length part of NDP16 plus a set
amount of DPEs fit within the URB.

Note that this commit alone does not fully address the OoB read.
The limit on the amount of DPEs needs to be enforced separately.

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-2025-21742 has been found in Kernel.
Attackers can target a specific entry point like wNdpIndex over the network to misuse the product.
Confidential information can be exposed externally.
What to do: upgrade Kernel to 6.6.78, 6.12.14, 6.13.3 or later.
If unsure, ask your IT team or search "Kernel CVE-2025-21742" on the vendor's site.

CVE-2025-21742 (Kernel)
Attack vector: local / no user interaction
Attack surface: wNdpIndex
Patched: 6.6.78, 6.12.14, 6.13.3 — 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. Attackers reach the vulnerable code path via wNdpIndex.

📍 Affected scope

Check the vendor advisory for the affected versions of Kernel. Attack surface: wNdpIndex.

🔥 Severity

Severity: ?. Confidential information can be exposed externally.

🔧 How to fix

Update to 6.6.78, 6.12.14, 6.13.3.

🛡️ 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 6.6.78, 6.12.14, 6.13.3
```
ステージング環境で 6.6.78, 6.12.14, 6.13.3 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":"6.5.0"},{"fixed":"6.6.78"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.14"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.13.3"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

BellSoft Alpaquita BELL-CVE-2025-21742 linux-lts Fixed in: 6.12.41-r0
Debian DEBIAN-CVE-2025-21742 linux Fixed in: 6.12.15-1
Ubuntu UBUNTU-CVE-2025-21742 linux-hwe-edge