Linux Distros のパッチ未適用の脆弱性: CVE-2025-21823

medium Nessus プラグイン ID 230615

概要

Linux/Unix ホストには、ベンダーにより修正されていないことを示す脆弱性を持つ複数のパッケージがインストールされています。

説明

Linux/Unix ホストには、ベンダーが提供するパッチが利用できない脆弱性の影響を受ける複数のパッケージがインストールされています。

- Linux カーネルにおいて、以下の脆弱性は解決されました: batman-adv: Drop unmanaged ELP metric worker The ELP worker needs to calculate new metric values for all neighbors reachable over an interface. Some of the used metric sources require locks which might need to sleep. This sleep is incompatible with the RCU list iterator used for the recorded neighbors. The initial approach to work around of this problem was to queue another work item per neighbor and then run this in a new context.
Even when this solved the RCU vs might_sleep() conflict, it has a major problems: Nothing was stopping the work item in case it is not needed anymore - for example because one of the related interfaces was removed or the batman-adv module was unloaded - resulting in potential invalid memory accesses. Directly canceling the metric worker also has various problems: * cancel_work_sync for a to-be-deactivated interface is called with rtnl_lock held. But the code in the ELP metric worker also tries to use rtnl_lock() - which will never return in this case. This also means that cancel_work_sync would never return because it is waiting for the worker to finish. * iterating over the neighbor list for the to-be-deactivated interface is currently done using the RCU specific methods. Which means that it is possible to miss items when iterating over it without the associated spinlock - a behaviour which is acceptable for a periodic metric check but not for a cleanup routine (which must stop all still running workers) The better approch is to get rid of the per interface neighbor metric worker and handle everything in the interface worker. The original problems are solved by: * creating a list of neighbors which require new metric information inside the RCU protected context, gathering the metric according to the new list outside the RCU protected context * only use rcu_trylock inside metric gathering code to avoid a deadlock when the cancel_delayed_work_sync is called in the interface removal code (which is called with the rtnl_lock held) (CVE-2025-21823)

Nessus は、ベンダーによって報告されたパッケージの存在に依存していることに注意してください。

ソリューション

現時点で既知の解決策はありません。

プラグインの詳細

深刻度: Medium

ID: 230615

ファイル名: unpatched_CVE_2025_21823.nasl

バージョン: 1.1

タイプ: local

エージェント: unix

ファミリー: Misc.

公開日: 2025/3/6

更新日: 2025/3/6

サポートされているセンサー: Nessus Agent, Nessus

リスク情報

VPR

リスクファクター: Medium

スコア: 5.0

CVSS v2

リスクファクター: Medium

基本値: 5

現状値: 3.7

ベクトル: CVSS2#AV:N/AC:L/Au:N/C:P/I:N/A:N

CVSS スコアのソース: CVE-2025-21823

CVSS v3

リスクファクター: Medium

基本値: 6.1

現状値: 5.3

ベクトル: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H

現状ベクトル: CVSS:3.0/E:U/RL:O/RC:C

脆弱性情報

必要な KB アイテム: Host/local_checks_enabled, Host/cpu, global_settings/vendor_unpatched

エクスプロイトの容易さ: No known exploits are available

脆弱性公開日: 2025/2/27

参照情報

CVE: CVE-2025-21823