Vulnerability in Kernel (CVE-2025-21658)

Summary

Vulnerability in Kernel (CVE-2025-21658). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 6.6.72, 6.12.10 or later.

Original description

The description as published by the source.

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

btrfs: avoid NULL pointer dereference if no valid extent tree

[BUG]
Syzbot reported a crash with the following call trace:

BTRFS info (device loop0): scrub: started on devid 1
BUG: kernel NULL pointer dereference, address: 0000000000000208
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 106e70067 P4D 106e70067 PUD 107143067 PMD 0
Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI
CPU: 1 UID: 0 PID: 689 Comm: repro Kdump: loaded Tainted: G O 6.13.0-rc4-custom+ #206
Tainted: [O]=OOT_MODULE
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS unknown 02/02/2022
RIP: 0010:find_first_extent_item+0x26/0x1f0 [btrfs]
Call Trace:

scrub_find_fill_first_stripe+0x13d/0x3b0 [btrfs]
scrub_simple_mirror+0x175/0x260 [btrfs]
scrub_stripe+0x5d4/0x6c0 [btrfs]
scrub_chunk+0xbb/0x170 [btrfs]
scrub_enumerate_chunks+0x2f4/0x5f0 [btrfs]
btrfs_scrub_dev+0x240/0x600 [btrfs]
btrfs_ioctl+0x1dc8/0x2fa0 [btrfs]
? do_sys_openat2+0xa5/0xf0
__x64_sys_ioctl+0x97/0xc0
do_syscall_64+0x4f/0x120
entry_SYSCALL_64_after_hwframe+0x76/0x7e

[CAUSE]
The reproducer is using a corrupted image where extent tree root is
corrupted, thus forcing to use "rescue=all,ro" mount option to mount the
image.

Then it triggered a scrub, but since scrub relies on extent tree to find
where the data/metadata extents are, scrub_find_fill_first_stripe()
re…

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-2025-21658 has been found in Kernel.
Risk of unauthorized operations or information disclosure.
What to do: upgrade Kernel to 6.6.72, 6.12.10 or later.
If unsure, ask your IT team or search "Kernel CVE-2025-21658" on the vendor's site.

CVE-2025-21658 (Kernel)
Attack vector: local / no user interaction
Patched: 6.6.72, 6.12.10 — 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 6.6.72, 6.12.10.

🛡️ 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 6.6.72, 6.12.10
```
ステージング環境で 6.6.72, 6.12.10 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":"5.11.0"},{"fixed":"6.6.72"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.10"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

BellSoft Alpaquita BELL-CVE-2025-21658 linux-lts
Debian DEBIAN-CVE-2025-21658 linux
Ubuntu UBUNTU-CVE-2025-21658 linux-hwe-edge