Vulnerability in Linux kernel (CVE-2025-68209)

Summary

Vulnerability in Linux kernel (CVE-2025-68209). 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:

mlx5: Fix default values in create CQ

Currently, CQs without a completion function are assigned the
mlx5_add_cq_to_tasklet function by default. This is problematic since
only user CQs created through the mlx5_ib driver are intended to use
this function.

Additionally, all CQs that will use doorbells instead of polling for
completions must call mlx5_cq_arm. However, the default CQ creation flow
leaves a valid value in the CQ's arm_db field, allowing FW to send
interrupts to polling-only CQs in certain corner cases.

These two factors would allow a polling-only kernel CQ to be triggered
by an EQ interrupt and call a completion function intended only for user
CQs, causing a null pointer exception.

Some areas in the driver have prevented this issue with one-off fixes
but did not address the root cause.

This patch fixes the described issue by adding defaults to the create CQ
flow. It adds a default dummy completion function to protect against
null pointer exceptions, and it sets an invalid command sequence number
by default in kernel CQs to prevent the FW from sending an interrupt to
the CQ until it is armed. User CQs are responsible for their own
initialization values.

Callers of mlx5_core_create_cq are responsible for changing the
completion function and arming the CQ per their needs.

Source: NIST National Vulnerability Database NVD

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-2025-68209 has been found in Linux kernel.
Risk of unauthorized operations or information disclosure.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2025-68209" on the vendor's site.

CVE-2025-68209 (Linux kernel)
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 Linux kernel.

📍 Affected scope

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

🔥 Severity

Severity: ?. 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
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
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。

Fix status by distribution

Fixed packages published by each distribution for this CVE

BellSoft Alpaquita BELL-CVE-2025-68209 linux-lts
Debian DEBIAN-CVE-2025-68209 linux
Ubuntu UBUNTU-CVE-2025-68209 linux-hwe-edge

References

web git.kernel.org
web git.kernel.org