Vulnerability in Kernel (CVE-2026-23077)

Summary

Vulnerability in Kernel (CVE-2026-23077). Successful exploitation can lead to full system takeover. Mitigation: upgrade to 6.18.8 or later.

Original description

The description as published by the source.

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

mm/vma: fix anon_vma UAF on mremap() faulted, unfaulted merge

Patch series "mm/vma: fix anon_vma UAF on mremap() faulted, unfaulted
merge", v2.

Commit 879bca0a2c4f ("mm/vma: fix incorrectly disallowed anonymous VMA
merges") introduced the ability to merge previously unavailable VMA merge
scenarios.

However, it is handling merges incorrectly when it comes to mremap() of a
faulted VMA adjacent to an unfaulted VMA. The issues arise in three
cases:

Previous VMA unfaulted:
```
       copied -----|
                   v
```
|-----------|.............|
| unfaulted |(faulted VMA)|
|-----------|.............|
prev

Next VMA unfaulted:

       copied -----|
                   v
         |.............|-----------|
         |(faulted VMA)| unfaulted |
             |.............|-----------|
                       next

Both adjacent VMAs unfaulted:
```
       copied -----|
                   v
```
|-----------|.............|-----------|
| unfaulted |(faulted VMA)| unfaulted |
|-----------|.............|-----------|
prev next

This series fixes each of these cases, and introduces self tests to assert
that the issues are corrected.

I also test a further case which was already handled, to assert that my
changes continues to correctly handle it:

prev unfaulted, next faulted:
```
       copied -----|…
```

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-2026-23077 has been found in Kernel.
Successful exploitation can lead to full system takeover.
What to do: upgrade Kernel to 6.18.8 or later.
If unsure, ask your IT team or search "Kernel CVE-2026-23077" on the vendor's site.

CVE-2026-23077 (Kernel)
Attack vector: local / no user interaction
Patched: 6.18.8 — 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 6.18.8.

🛡️ 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 6.18.8
```
ステージング環境で 6.18.8 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":"6.16.0"},{"fixed":"6.18.8"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

BellSoft Alpaquita BELL-CVE-2026-23077 linux-lts Fixed in: 6.18.35-r1
Debian DEBIAN-CVE-2026-23077 linux Fixed in: 6.18.8-1
Ubuntu UBUNTU-CVE-2026-23077 linux-hwe-edge