Vulnerability in Kernel (CVE-2023-52786)

Summary

Vulnerability in Kernel (CVE-2023-52786). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 6.5.13, 6.6.3 or later.

Original description

The description as published by the source.

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

ext4: fix racy may inline data check in dio write

syzbot reports that the following warning from ext4_iomap_begin()
triggers as of the commit referenced below:

    if (WARN_ON_ONCE(ext4_has_inline_data(inode)))
            return -ERANGE;

This occurs during a dio write, which is never expected to encounter
an inode with inline data. To enforce this behavior,
ext4_dio_write_iter() checks the current inline state of the inode
and clears the MAY_INLINE_DATA state flag to either fall back to
buffered writes, or enforce that any other writers in progress on
the inode are not allowed to create inline data.

The problem is that the check for existing inline data and the state
flag can span a lock cycle. For example, if the ilock is originally
locked shared and subsequently upgraded to exclusive, another writer
may have reacquired the lock and created inline data before the dio
write task acquires the lock and proceeds.

The commit referenced below loosens the lock requirements to allow
some forms of unaligned dio writes to occur under shared lock, but
AFAICT the inline data check was technically already racy for any
dio write that would have involved a lock cycle. Regardless, lift
clearing of the state bit to the same lock critical section that
checks for preexisting inline data on the inode to close the race.

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-2023-52786 has been found in Kernel.
Risk of unauthorized operations or information disclosure.
What to do: upgrade Kernel to 6.5.13, 6.6.3 or later.
If unsure, ask your IT team or search "Kernel CVE-2023-52786" on the vendor's site.

CVE-2023-52786 (Kernel)
Patched: 6.5.13, 6.6.3 — 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 6.5.13, 6.6.3.

🛡️ 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 6.5.13, 6.6.3
```
ステージング環境で 6.5.13, 6.6.3 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":"6.5.0"},{"fixed":"6.5.13"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.6.0"},{"fixed":"6.6.3"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

Debian DEBIAN-CVE-2023-52786 linux Fixed in: 6.6.8-1