Vulnerability in Kernel (CVE-2026-23235)

Summary

Vulnerability in Kernel (CVE-2026-23235). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 5.10.251, 5.15.201, 6.1.164, 6.6.127, 6.12.74, 6.18.13, 6.19.3 or later.

Original description

The description as published by the source.

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

f2fs: fix out-of-bounds access in sysfs attribute read/write

Some f2fs sysfs attributes suffer from out-of-bounds memory access and
incorrect handling of integer values whose size is not 4 bytes.

For example:
vm:# echo 65537 > /sys/fs/f2fs/vde/carve_out
vm:# cat /sys/fs/f2fs/vde/carve_out
65537
vm:# echo 4294967297 > /sys/fs/f2fs/vde/atgc_age_threshold
vm:# cat /sys/fs/f2fs/vde/atgc_age_threshold
1

carve_out maps to {struct f2fs_sb_info}->carve_out, which is a 8-bit
integer. However, the sysfs interface allows setting it to a value
larger than 255, resulting in an out-of-range update.

atgc_age_threshold maps to {struct atgc_management}->age_threshold,
which is a 64-bit integer, but its sysfs interface cannot correctly set
values larger than UINT_MAX.

The root causes are:

__sbi_store() treats all default values as unsigned int, which
prevents updating integers larger than 4 bytes and causes out-of-bounds
writes for integers smaller than 4 bytes.
f2fs_sbi_show() also assumes all default values are unsigned int,
leading to out-of-bounds reads and incorrect access to integers larger
than 4 bytes.

This patch introduces {struct f2fs_attr}->size to record the actual size
of the integer associated with each sysfs attribute. With this
information, sysfs read and write operations can correctly access and
update values according to their real data size, avoiding memory
corruption and truncation.

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-2026-23235 has been found in Kernel.
Risk of unauthorized operations or information disclosure.
What to do: upgrade Kernel to 5.10.251, 5.15.201, 6.1.164, 6.6.127, 6.12.74, 6.18.13, 6.19.3 or later.
If unsure, ask your IT team or search "Kernel CVE-2026-23235" on the vendor's site.

CVE-2026-23235 (Kernel)
Patched: 5.10.251, 5.15.201, 6.1.164, 6.6.127, 6.12.74, 6.18.13, 6.19.3 — 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: ?. Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 5.10.251, 5.15.201, 6.1.164, 6.6.127, 6.12.74, 6.18.13, 6.19.3.

🛡️ 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 5.10.251, 5.15.201, 6.1.164, 6.6.127, 6.12.74, 6.18.13, 6.19.3
```
ステージング環境で 5.10.251, 5.15.201, 6.1.164, 6.6.127, 6.12.74, 6.18.13, 6.19.3 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":"3.12.0"},{"fixed":"5.10.251"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.201"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.164"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.127"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.74"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.13"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.3"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

BellSoft Alpaquita BELL-CVE-2026-23235 linux-lts Fixed in: 6.1.164-r0
Debian DEBIAN-CVE-2026-23235 linux Fixed in: 5.10.251-1
Ubuntu UBUNTU-CVE-2026-23235 linux