Vulnerability in Kernel (CVE-2024-56673)

Summary

Vulnerability in Kernel (CVE-2024-56673). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 6.12.6 or later.

Original description

The description as published by the source.

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

riscv: mm: Do not call pmd dtor on vmemmap page table teardown

The vmemmap's, which is used for RV64 with SPARSEMEM_VMEMMAP, page
tables are populated using pmd (page middle directory) hugetables.
However, the pmd allocation is not using the generic mechanism used by
the VMA code (e.g. pmd_alloc()), or the RISC-V specific
create_pgd_mapping()/alloc_pmd_late(). Instead, the vmemmap page table
code allocates a page, and calls vmemmap_set_pmd(). This results in
that the pmd ctor is not called, nor would it make sense to do so.

Now, when tearing down a vmemmap page table pmd, the cleanup code
would unconditionally, and incorrectly call the pmd dtor, which
results in a crash (best case).

This issue was found when running the HMM selftests:

| tools/testing/selftests/mm# ./test_hmm.sh smoke
| ... # when unloading the test_hmm.ko module
| page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10915b
| flags: 0x1000000000000000(node=0|zone=1)
| raw: 1000000000000000 0000000000000000 dead000000000122 0000000000000000
| raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
| page dumped because: VM_BUG_ON_PAGE(ptdesc->pmd_huge_pte)
| ------------[ cut here ]------------
| kernel BUG at include/linux/mm.h:3080!
| Kernel BUG [#1]
| Modules linked in: test_hmm(-) sch_fq_codel fuse drm drm_panel_orientation_quirks backlight dm_mod
| CPU: 1 UID: 0 PID: 514 Comm:…

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-2024-56673 has been found in Kernel.
Risk of unauthorized operations or information disclosure.
What to do: upgrade Kernel to 6.12.6 or later.
If unsure, ask your IT team or search "Kernel CVE-2024-56673" on the vendor's site.

CVE-2024-56673 (Kernel)
Attack vector: local / no user interaction
Patched: 6.12.6 — 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 6.12.6.

🛡️ 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 6.12.6
```
ステージング環境で 6.12.6 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":"6.11.0"},{"fixed":"6.12.6"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

BellSoft Alpaquita BELL-CVE-2024-56673 linux-lts Fixed in: 6.12.41-r0
Debian DEBIAN-CVE-2024-56673 linux Fixed in: 6.12.6-1