Vulnerability in Kernel (CVE-2023-53243)

Summary

Vulnerability in Kernel (CVE-2023-53243). Risk of unauthorized operations or information disclosure. Exploitable via btrfs_reduce_alloc_profile. Mitigation: upgrade to 5.10.188, 5.15.121, 6.1.39, 6.4.4 or later.

Original description

The description as published by the source.

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

btrfs: add handling for RAID1C23/DUP to btrfs_reduce_alloc_profile

Callers of btrfs_reduce_alloc_profile expect it to return exactly
one allocation profile flag, and failing to do so may ultimately
result in a WARN_ON and remount-ro when allocating new blocks, like
the below transaction abort on 6.1.

btrfs_reduce_alloc_profile has two ways of determining the profile,
first it checks if a conversion balance is currently running and
uses the profile we're converting to. If no balance is currently
running, it returns the max-redundancy profile which at least one
block in the selected block group has.

This works by simply checking each known allocation profile bit in
redundancy order. However, btrfs_reduce_alloc_profile has not been
updated as new flags have been added - first with the DUP profile
and later with the RAID1C34 profiles.

Because of the way it checks, if we have blocks with different
profiles and at least one is known, that profile will be selected.
However, if none are known we may return a flag set with multiple
allocation profiles set.

This is currently only possible when a balance from one of the three
unhandled profiles to another of the unhandled profiles is canceled
after allocating at least one block using the new profile.

In that case, a transaction abort like the below will occur and the
filesystem will need to be mounted with -o skip_balance to get it
mounted rw again (but t…

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-2023-53243 has been found in Kernel.
Attackers can target a specific entry point like btrfs_reduce_alloc_profile over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade Kernel to 5.10.188, 5.15.121, 6.1.39, 6.4.4 or later.
If unsure, ask your IT team or search "Kernel CVE-2023-53243" on the vendor's site.

CVE-2023-53243 (Kernel)
Attack vector: local / no user interaction
Attack surface: btrfs_reduce_alloc_profile / DUP
Patched: 5.10.188, 5.15.121, 6.1.39, 6.4.4 — 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. Attackers reach the vulnerable code path via btrfs_reduce_alloc_profile.

📍 Affected scope

Check the vendor advisory for the affected versions of Kernel. Attack surface: btrfs_reduce_alloc_profile / DUP.

🔥 Severity

Severity: ?. Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 5.10.188, 5.15.121, 6.1.39, 6.4.4.

🛡️ 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 5.10.188, 5.15.121, 6.1.39, 6.4.4
```
ステージング環境で 5.10.188, 5.15.121, 6.1.39, 6.4.4 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":"5.5.0"},{"fixed":"5.10.188"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.121"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.39"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.4.4"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

Debian DEBIAN-CVE-2023-53243 linux Fixed in: 5.10.191-1
Ubuntu UBUNTU-CVE-2023-53243 linux-hwe-edge