Categories
CVE-2025-21676 high CVSS 7.5

Vulnerability in Linux kernel (CVE-2025-21676)

Summary

Vulnerability in Linux kernel (CVE-2025-21676). Risk of unauthorized operations or information disclosure.

Original description

The description as published by the source.

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

net: fec: handle page_pool_dev_alloc_pages error

The fec_enet_update_cbd function calls page_pool_dev_alloc_pages but did
not handle the case when it returned NULL. There was a WARN_ON(!new_page)
but it would still proceed to use the NULL pointer and then crash.

This case does seem somewhat rare but when the system is under memory
pressure it can happen. One case where I can duplicate this with some
frequency is when writing over a smbd share to a SATA HDD attached to an
imx6q.

Setting /proc/sys/vm/min_free_kbytes to higher values also seems to solve
the problem for my test case. But it still seems wrong that the fec driver
ignores the memory allocation error and can crash.

This commit handles the allocation error by dropping the current packet.

Source: NIST National Vulnerability Database NVD GitHub Advisory

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-2025-21676 has been found in Linux kernel.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2025-21676" on the vendor's site.

CVE-2025-21676 (Linux kernel) — CWE-476 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
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 (CWE-476) exists in Linux kernel.

📍 Affected scope

Check the vendor advisory for the affected versions of Linux kernel.

🔥 Severity

Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to the patched release per vendor advisory.

🛡️ 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. Audit SBOM/dependencies to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify
    Audit SBOM/dependencies for affected components.

    資産台帳・SBOM・依存マニフェストで Linux kernel を使っているサービスとバージョンを洗い出す。

  2. 2
    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":"6.1.0"},{"fixed":"6.1.167"}]},{"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

References

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