Vulnerability in Kernel (CVE-2026-31589)

Summary

Vulnerability in Kernel (CVE-2026-31589). Successful exploitation can lead to full system takeover. Mitigation: upgrade to 6.18.27, 6.19.14, 7.0.1 or later.

Original description

The description as published by the source.

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

mm: call ->free_folio() directly in folio_unmap_invalidate()

We can only call filemap_free_folio() if we have a reference to (or hold a
lock on) the mapping. Otherwise, we've already removed the folio from the
mapping so it no longer pins the mapping and the mapping can be removed,
causing a use-after-free when accessing mapping->a_ops.

Follow the same pattern as __remove_mapping() and load the free_folio
function pointer before dropping the lock on the mapping. That lets us
make filemap_free_folio() static as this was the only caller outside
filemap.c.

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-2026-31589 has been found in Kernel.
Successful exploitation can lead to full system takeover.
What to do: upgrade Kernel to 6.18.27, 6.19.14, 7.0.1 or later.
If unsure, ask your IT team or search "Kernel CVE-2026-31589" on the vendor's site.

CVE-2026-31589 (Kernel)
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 6.18.27, 6.19.14, 7.0.1 — 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 6.18.27, 6.19.14, 7.0.1.

🛡️ 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 6.18.27, 6.19.14, 7.0.1
```
ステージング環境で 6.18.27, 6.19.14, 7.0.1 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":"6.14.0"},{"fixed":"6.18.27"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.14"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.20.0"},{"fixed":"7.0.1"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

BellSoft Alpaquita BELL-CVE-2026-31589 linux-lts Fixed in: 6.18.35-r1
Debian DEBIAN-CVE-2026-31589 linux Fixed in: 6.19.14-1
Ubuntu UBUNTU-CVE-2026-31589 linux-hwe-edge