Vulnerability in Kernel (CVE-2025-21680)

Summary

Vulnerability in Kernel (CVE-2025-21680). Successful exploitation can lead to full system takeover. Mitigation: upgrade to 5.15.177, 6.1.127, 6.6.74, 6.12.11 or later.

Original description

The description as published by the source.

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

pktgen: Avoid out-of-bounds access in get_imix_entries

Passing a sufficient amount of imix entries leads to invalid access to the
pkt_dev->imix_entries array because of the incorrect boundary check.

UBSAN: array-index-out-of-bounds in net/core/pktgen.c:874:24
index 20 is out of range for type 'imix_pkt [20]'
CPU: 2 PID: 1210 Comm: bash Not tainted 6.10.0-rc1 #121
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
Call Trace:

dump_stack_lvl lib/dump_stack.c:117
__ubsan_handle_out_of_bounds lib/ubsan.c:429
get_imix_entries net/core/pktgen.c:874
pktgen_if_write net/core/pktgen.c:1063
pde_write fs/proc/inode.c:334
proc_reg_write fs/proc/inode.c:346
vfs_write fs/read_write.c:593
ksys_write fs/read_write.c:644
do_syscall_64 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe arch/x86/entry/entry_64.S:130

Found by Linux Verification Center (linuxtesting.org) with SVACE.

[ fp: allow to fill the array completely; minor changelog cleanup ]

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-2025-21680 has been found in Kernel.
Successful exploitation can lead to full system takeover.
What to do: upgrade Kernel to 5.15.177, 6.1.127, 6.6.74, 6.12.11 or later.
If unsure, ask your IT team or search "Kernel CVE-2025-21680" on the vendor's site.

CVE-2025-21680 (Kernel)
Attack vector: local / no user interaction
Patched: 5.15.177, 6.1.127, 6.6.74, 6.12.11 — 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 5.15.177, 6.1.127, 6.6.74, 6.12.11.

🛡️ 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 5.15.177, 6.1.127, 6.6.74, 6.12.11
```
ステージング環境で 5.15.177, 6.1.127, 6.6.74, 6.12.11 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":"5.15.0"},{"fixed":"5.15.177"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.127"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.74"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.11"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

BellSoft Alpaquita BELL-CVE-2025-21680 linux-lts Fixed in: 6.1.127-r0
Debian DEBIAN-CVE-2025-21680 linux Fixed in: 6.1.128-1
Ubuntu UBUNTU-CVE-2025-21680 linux-hwe-edge