Vulnerability in Kernel (CVE-2025-68771)

Summary

Vulnerability in Kernel (CVE-2025-68771). Risk of unauthorized operations or information disclosure. Exploitable via cl_next_free_rec. Mitigation: upgrade to 5.10.248, 5.15.198, 6.1.160, 6.6.120, 6.12.64, 6.18.3 or later.

Original description

The description as published by the source.

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

ocfs2: fix kernel BUG in ocfs2_find_victim_chain

syzbot reported a kernel BUG in ocfs2_find_victim_chain() because the
cl_next_free_rec field of the allocation chain list (next free slot in
the chain list) is 0, triggring the BUG_ON(!cl->cl_next_free_rec)
condition in ocfs2_find_victim_chain() and panicking the kernel.

To fix this, an if condition is introduced in ocfs2_claim_suballoc_bits(),
just before calling ocfs2_find_victim_chain(), the code block in it being
executed when either of the following conditions is true:

cl_next_free_rec is equal to 0, indicating that there are no free
chains in the allocation chain list
cl_next_free_rec is greater than cl_count (the total number of
chains in the allocation chain list)

Either of them being true is indicative of the fact that there are no
chains left for usage.

This is addressed using ocfs2_error(), which prints
the error log for debugging purposes, rather than panicking the kernel.

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-2025-68771 has been found in Kernel.
Attackers can target a specific entry point like cl_next_free_rec over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade Kernel to 5.10.248, 5.15.198, 6.1.160, 6.6.120, 6.12.64, 6.18.3 or later.
If unsure, ask your IT team or search "Kernel CVE-2025-68771" on the vendor's site.

CVE-2025-68771 (Kernel)
Attack surface: cl_next_free_rec / cl_count
Patched: 5.10.248, 5.15.198, 6.1.160, 6.6.120, 6.12.64, 6.18.3 — 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. Attackers reach the vulnerable code path via cl_next_free_rec.

📍 Affected scope

Check the vendor advisory for the affected versions of Kernel. Attack surface: cl_next_free_rec / cl_count.

🔥 Severity

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

🔧 How to fix

Update to 5.10.248, 5.15.198, 6.1.160, 6.6.120, 6.12.64, 6.18.3.

🛡️ 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 5.10.248, 5.15.198, 6.1.160, 6.6.120, 6.12.64, 6.18.3
```
ステージング環境で 5.10.248, 5.15.198, 6.1.160, 6.6.120, 6.12.64, 6.18.3 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":"2.6.16"},{"fixed":"5.10.248"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.198"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.160"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.120"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.64"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.3"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

BellSoft Alpaquita BELL-CVE-2025-68771 linux-lts Fixed in: 6.1.161-r0
Debian DEBIAN-CVE-2025-68771 linux Fixed in: 5.10.249-1
Ubuntu UBUNTU-CVE-2025-68771 linux