Vulnerability in Kernel (CVE-2025-21747)

Summary

Vulnerability in Kernel (CVE-2025-21747). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 6.13.3 or later.

Original description

The description as published by the source.

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

drm/ast: astdp: Fix timeout for enabling video signal

The ASTDP transmitter sometimes takes up to 1 second for enabling the
video signal, while the timeout is only 200 msec. This results in a
kernel error message. Increase the timeout to 1 second. An example
of the error message is shown below.

[ 697.084433] ------------[ cut here ]------------
[ 697.091115] ast 0000:02:00.0: [drm] drm_WARN_ON(!__ast_dp_wait_enable(ast, enabled))
[ 697.091233] WARNING: CPU: 1 PID: 160 at drivers/gpu/drm/ast/ast_dp.c:232 ast_dp_set_enable+0x123/0x140 [ast]
[...]
[ 697.272469] RIP: 0010:ast_dp_set_enable+0x123/0x140 [ast]
[...]
[ 697.415283] Call Trace:
[ 697.420727]
[ 697.425908] ? show_trace_log_lvl+0x196/0x2c0
[ 697.433304] ? show_trace_log_lvl+0x196/0x2c0
[ 697.440693] ? drm_atomic_helper_commit_modeset_enables+0x30a/0x470
[ 697.450115] ? ast_dp_set_enable+0x123/0x140 [ast]
[ 697.458059] ? __warn.cold+0xaf/0xca
[ 697.464713] ? ast_dp_set_enable+0x123/0x140 [ast]
[ 697.472633] ? report_bug+0x134/0x1d0
[ 697.479544] ? handle_bug+0x58/0x90
[ 697.486127] ? exc_invalid_op+0x13/0x40
[ 697.492975] ? asm_exc_invalid_op+0x16/0x20
[ 697.500224] ? preempt_count_sub+0x14/0xc0
[ 697.507473] ? ast_dp_set_enable+0x123/0x140 [ast]
[ 697.515377] ? ast_dp_set_enable+0x123/0x140 [ast]
[ 697.523227] drm_atomic_helper_commit_modeset_enables+0x30a/0x470
[ 697.532388] drm_atomic_helper_commit_tail+0x58/0x9…

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-2025-21747 has been found in Kernel.
Risk of unauthorized operations or information disclosure.
What to do: upgrade Kernel to 6.13.3 or later.
If unsure, ask your IT team or search "Kernel CVE-2025-21747" on the vendor's site.

CVE-2025-21747 (Kernel)
Patched: 6.13.3 — 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 6.13.3.

🛡️ 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 6.13.3
```
ステージング環境で 6.13.3 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":"6.13.0"},{"fixed":"6.13.3"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

BellSoft Alpaquita BELL-CVE-2025-21747 linux-lts Fixed in: 6.18.35-r1