Vulnerability in Linux kernel (CVE-2025-68262)

Summary

Vulnerability in Linux kernel (CVE-2025-68262). Risk of unauthorized operations or information disclosure.

Original description

The description as published by the source.

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

crypto: zstd - fix double-free in per-CPU stream cleanup

The crypto/zstd module has a double-free bug that occurs when multiple
tfms are allocated and freed.

The issue happens because zstd_streams (per-CPU contexts) are freed in
zstd_exit() during every tfm destruction, rather than being managed at
the module level. When multiple tfms exist, each tfm exit attempts to
free the same shared per-CPU streams, resulting in a double-free.

This leads to a stack trace similar to:

BUG: Bad page state in process kworker/u16:1 pfn:106fd93
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x106fd93
flags: 0x17ffffc0000000(node=0|zone=2|lastcpupid=0x1fffff)
page_type: 0xffffffff()
raw: 0017ffffc0000000 dead000000000100 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: nonzero entire_mapcount
Modules linked in: ...
CPU: 3 UID: 0 PID: 2506 Comm: kworker/u16:1 Kdump: loaded Tainted: G B
Hardware name: ...
Workqueue: btrfs-delalloc btrfs_work_helper
Call Trace:

dump_stack_lvl+0x5d/0x80
bad_page+0x71/0xd0
free_unref_page_prepare+0x24e/0x490
free_unref_page+0x60/0x170
crypto_acomp_free_streams+0x5d/0xc0
crypto_acomp_exit_tfm+0x23/0x50
crypto_destroy_tfm+0x60/0xc0
...

Change the lifecycle management of zstd_streams to free the streams only
once during module cleanup.

Source: NIST National Vulnerability Database NVD

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-2025-68262 has been found in Linux kernel.
Risk of unauthorized operations or information disclosure.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2025-68262" on the vendor's site.

CVE-2025-68262 (Linux kernel)
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 Linux kernel.

📍 Affected scope

Check the vendor advisory for the affected versions of Linux kernel.

🔥 Severity

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

🔧 How to fix

Update to the patched release per vendor advisory.

🛡️ 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. Audit SBOM/dependencies to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

1
Identify exposure identify
```
Audit SBOM/dependencies for affected components.
```
資産台帳・SBOM・依存マニフェストで Linux kernel を使っているサービスとバージョンを洗い出す。
2
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。

Fix status by distribution

Fixed packages published by each distribution for this CVE

BellSoft Alpaquita BELL-CVE-2025-68262 linux-lts Fixed in: 6.18.35-r1
Debian DEBIAN-CVE-2025-68262 linux Fixed in: 6.17.12-1
Ubuntu UBUNTU-CVE-2025-68262 linux-hwe-edge