Vulnerability in Kernel (CVE-2024-56558)

Summary

Vulnerability in Kernel (CVE-2024-56558). Successful exploitation can lead to full system takeover. Exploitable via e_show. Mitigation: upgrade to 5.4.287, 5.10.231, 5.15.174, 6.1.120, 6.6.64, 6.12.4 or later.

Original description

The description as published by the source.

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

nfsd: make sure exp active before svc_export_show

The function e_show was called with protection from RCU. This only
ensures that exp will not be freed. Therefore, the reference count for
exp can drop to zero, which will trigger a refcount use-after-free
warning when exp_get is called. To resolve this issue, use
cache_get_rcu to ensure that exp remains active.

------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 3 PID: 819 at lib/refcount.c:25
refcount_warn_saturate+0xb1/0x120
CPU: 3 UID: 0 PID: 819 Comm: cat Not tainted 6.12.0-rc3+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.16.1-2.fc37 04/01/2014
RIP: 0010:refcount_warn_saturate+0xb1/0x120
...
Call Trace:

e_show+0x20b/0x230 [nfsd]
seq_read_iter+0x589/0x770
seq_read+0x1e5/0x270
vfs_read+0x125/0x530
ksys_read+0xc1/0x160
do_syscall_64+0x5f/0x170
entry_SYSCALL_64_after_hwframe+0x76/0x7e

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-2024-56558 has been found in Kernel.
Attackers can target a specific entry point like e_show over the network to misuse the product.
Successful exploitation can lead to full system takeover.
What to do: upgrade Kernel to 5.4.287, 5.10.231, 5.15.174, 6.1.120, 6.6.64, 6.12.4 or later.
If unsure, ask your IT team or search "Kernel CVE-2024-56558" on the vendor's site.

CVE-2024-56558 (Kernel)
Attack vector: local / no user interaction
Attack surface: e_show / exp / exp_get / cache_get_rcu
Patched: 5.4.287, 5.10.231, 5.15.174, 6.1.120, 6.6.64, 6.12.4 — 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. Attackers reach the vulnerable code path via e_show.

📍 Affected scope

Check the vendor advisory for the affected versions of Kernel. Attack surface: e_show / exp / exp_get / cache_get_rcu.

🔥 Severity

Severity: ?. Successful exploitation can lead to full system takeover.

🔧 How to fix

Update to 5.4.287, 5.10.231, 5.15.174, 6.1.120, 6.6.64, 6.12.4.

🛡️ 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 5.4.287, 5.10.231, 5.15.174, 6.1.120, 6.6.64, 6.12.4
```
ステージング環境で 5.4.287, 5.10.231, 5.15.174, 6.1.120, 6.6.64, 6.12.4 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":"3.17.0"},{"fixed":"5.4.287"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.5.0"},{"fixed":"5.10.231"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.174"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.120"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.64"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.4"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

BellSoft Alpaquita BELL-CVE-2024-56558 linux-lts Fixed in: 6.1.120-r0
Debian DEBIAN-CVE-2024-56558 linux Fixed in: 5.10.234-1
Ubuntu UBUNTU-CVE-2024-56558 linux