Categories
CVE-2026-43477 medium CVSS 5.5

Vulnerability in Linux kernel (CVE-2026-43477)

Summary

Vulnerability in Linux kernel (CVE-2026-43477). 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:

drm/i915/vrr: Configure VRR timings after enabling TRANS_DDI_FUNC_CTL

Apparently ICL may hang with an MCE if we write TRANS_VRR_VMAX/FLIPLINE
before enabling TRANS_DDI_FUNC_CTL.

Personally I was only able to reproduce a hang (on an Dell XPS 7390
2-in-1) with an external display connected via a dock using a dodgy
type-C cable that made the link training fail. After the failed
link training the machine would hang. TGL seemed immune to the
problem for whatever reason.

BSpec does tell us to configure VRR after enabling TRANS_DDI_FUNC_CTL
as well. The DMC firmware also does the VRR restore in two stages:

  • first stage seems to be unconditional and includes TRANS_VRR_CTL
    and a few other VRR registers, among other things
  • second stage is conditional on the DDI being enabled,
    and includes TRANS_DDI_FUNC_CTL and TRANS_VRR_VMAX/VMIN/FLIPLINE,
    among other things

So let's reorder the steps to match to avoid the hang, and
toss in an extra WARN to make sure we don't screw this up later.

BSpec: 22243
(cherry picked from commit 93f3a267c3dd4d811b224bb9e179a10d81456a74)

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-2026-43477 has been found in Linux kernel.
Risk of unauthorized operations or information disclosure. CVSS score: 5.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-43477" on the vendor's site.

CVE-2026-43477 (Linux kernel) — CVSS v3 5.5
Attack vector: local / 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 (unclassified) exists in Linux kernel.

📍 Affected scope

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

🔥 Severity

Severity: Medium (CVSS 5.5/10). 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":"6.16.0"},{"fixed":"6.18.20"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.9"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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