Vulnerability in Kernel (CVE-2025-21866)

Summary

Vulnerability in Kernel (CVE-2025-21866). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 5.4.291, 5.10.235, 5.15.179, 6.1.130, 6.6.80, 6.12.17, 6.13.5 or later.

Original description

The description as published by the source.

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

powerpc/code-patching: Fix KASAN hit by not flagging text patching area as VM_ALLOC

Erhard reported the following KASAN hit while booting his PowerMac G4
with a KASAN-enabled kernel 6.13-rc6:

BUG: KASAN: vmalloc-out-of-bounds in copy_to_kernel_nofault+0xd8/0x1c8
Write of size 8 at addr f1000000 by task chronyd/1293

CPU: 0 UID: 123 PID: 1293 Comm: chronyd Tainted: G W 6.13.0-rc6-PMacG4 #2
Tainted: [W]=WARN
Hardware name: PowerMac3,6 7455 0x80010303 PowerMac
Call Trace:
[c2437590] [c1631a84] dump_stack_lvl+0x70/0x8c (unreliable)
[c24375b0] [c0504998] print_report+0xdc/0x504
[c2437610] [c050475c] kasan_report+0xf8/0x108
[c2437690] [c0505a3c] kasan_check_range+0x24/0x18c
[c24376a0] [c03fb5e4] copy_to_kernel_nofault+0xd8/0x1c8
[c24376c0] [c004c014] patch_instructions+0x15c/0x16c
[c2437710] [c00731a8] bpf_arch_text_copy+0x60/0x7c
[c2437730] [c0281168] bpf_jit_binary_pack_finalize+0x50/0xac
[c2437750] [c0073cf4] bpf_int_jit_compile+0xb30/0xdec
[c2437880] [c0280394] bpf_prog_select_runtime+0x15c/0x478
[c24378d0] [c1263428] bpf_prepare_filter+0xbf8/0xc14
[c2437990] [c12677ec] bpf_prog_create_from_user+0x258/0x2b4
[c24379d0] [c027111c] do_seccomp+0x3dc/0x1890
[c2437ac0] [c001d8e0] system_call_exception+0x2dc/0x420
[c2437f30] [c00281ac] ret_from_syscall+0x0/0x2c
--- interrupt: c00 at 0x5a1274
NIP: 005a1274 LR: 006a3b3c CTR: 005296c8
REGS: c2437f40 TRAP…

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-2025-21866 has been found in Kernel.
Risk of unauthorized operations or information disclosure.
What to do: upgrade Kernel to 5.4.291, 5.10.235, 5.15.179, 6.1.130, 6.6.80, 6.12.17, 6.13.5 or later.
If unsure, ask your IT team or search "Kernel CVE-2025-21866" on the vendor's site.

CVE-2025-21866 (Kernel)
Attack vector: local / no user interaction
Patched: 5.4.291, 5.10.235, 5.15.179, 6.1.130, 6.6.80, 6.12.17, 6.13.5 — 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 5.4.291, 5.10.235, 5.15.179, 6.1.130, 6.6.80, 6.12.17, 6.13.5.

🛡️ 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 5.4.291, 5.10.235, 5.15.179, 6.1.130, 6.6.80, 6.12.17, 6.13.5
```
ステージング環境で 5.4.291, 5.10.235, 5.15.179, 6.1.130, 6.6.80, 6.12.17, 6.13.5 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":"4.13.0"},{"fixed":"5.4.291"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.5.0"},{"fixed":"5.10.235"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.179"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.130"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.80"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.17"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.13.5"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

BellSoft Alpaquita BELL-CVE-2025-21866 linux-lts Fixed in: 6.1.130-r0
Debian DEBIAN-CVE-2025-21866 linux
Ubuntu UBUNTU-CVE-2025-21866 linux-azure