Vulnerability in Kernel (CVE-2025-21883)

Summary

Vulnerability in Kernel (CVE-2025-21883). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 6.6.81, 6.12.18, 6.13.6 or later.

Original description

The description as published by the source.

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

ice: Fix deinitializing VF in error path

If ice_ena_vfs() fails after calling ice_create_vf_entries(), it frees
all VFs without removing them from snapshot PF-VF mailbox list, leading
to list corruption.

Reproducer:
devlink dev eswitch set $PF1_PCI mode switchdev
ip l s $PF1 up
ip l s $PF1 promisc on
sleep 1
echo 1 > /sys/class/net/$PF1/device/sriov_numvfs
sleep 1
echo 1 > /sys/class/net/$PF1/device/sriov_numvfs

Trace (minimized):
list_add corruption. next->prev should be prev (ffff8882e241c6f0), but was 0000000000000000. (next=ffff888455da1330).
kernel BUG at lib/list_debug.c:29!
RIP: 0010:__list_add_valid_or_report+0xa6/0x100
ice_mbx_init_vf_info+0xa7/0x180 [ice]
ice_initialize_vf_entry+0x1fa/0x250 [ice]
ice_sriov_configure+0x8d7/0x1520 [ice]
? __percpu_ref_switch_mode+0x1b1/0x5d0
? __pfx_ice_sriov_configure+0x10/0x10 [ice]

Sometimes a KASAN report can be seen instead with a similar stack trace:
BUG: KASAN: use-after-free in __list_add_valid_or_report+0xf1/0x100

VFs are added to this list in ice_mbx_init_vf_info(), but only removed
in ice_free_vfs(). Move the removing to ice_free_vf_entries(), which is
also being called in other places where VFs are being removed (including
ice_free_vfs() itself).

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-2025-21883 has been found in Kernel.
Risk of unauthorized operations or information disclosure.
What to do: upgrade Kernel to 6.6.81, 6.12.18, 6.13.6 or later.
If unsure, ask your IT team or search "Kernel CVE-2025-21883" on the vendor's site.

CVE-2025-21883 (Kernel)
Patched: 6.6.81, 6.12.18, 6.13.6 — 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 6.6.81, 6.12.18, 6.13.6.

🛡️ 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 6.6.81, 6.12.18, 6.13.6
```
ステージング環境で 6.6.81, 6.12.18, 6.13.6 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":"6.4.0"},{"fixed":"6.6.81"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.18"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.13.6"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

BellSoft Alpaquita BELL-CVE-2025-21883 linux-lts Fixed in: 6.12.41-r0
Debian DEBIAN-CVE-2025-21883 linux Fixed in: 6.12.19-1
Ubuntu UBUNTU-CVE-2025-21883 linux-hwe-edge