---
cve: "CVE-2024-42109"
severity: "HIGH"
cvss: 7.8
epss: "25%"
vendor: "Linux"
kev: false
exploited: false
published: "2024-07-30 08:15:03"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-15T13:29:45+02:00"
---

# CVE-2024-42109

> 7.8 HIGH

## Beschreibung

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

netfilter: nf_tables: unconditionally flush pending work before notifier

syzbot reports:

KASAN: slab-uaf in nft_ctx_update include/net/netfilter/nf_tables.h:1831
KASAN: slab-uaf in nft_commit_release net/netfilter/nf_tables_api.c:9530
KASAN: slab-uaf int nf_tables_trans_destroy_work+0x152b/0x1750 net/netfilter/nf_tables_api.c:9597
Read of size 2 at addr ffff88802b0051c4 by task kworker/1:1/45
[..]
Workqueue: events nf_tables_trans_destroy_work
Call Trace:
 nft_ctx_update include/net/netfilter/nf_tables.h:1831 [inline]
 nft_commit_release net/netfilter/nf_tables_api.c:9530 [inline]
 nf_tables_trans_destroy_work+0x152b/0x1750 net/netfilter/nf_tables_api.c:9597

Problem is that the notifier does a conditional flush, but its possible
that the table-to-be-removed is still referenced by transactions being
processed by the worker, so we need to flush unconditionally.

We could make the flush_work depend on whether we found a table to delete
in nf-next to avoid the flush for most cases.

AFAICS this problem is only exposed in nf-next, with
commit e169285f8c56 ("netfilter: nf_tables: do not store nft_ctx in transaction objects"),
with this commit applied there is an unconditional fetch of
table->family which is whats triggering the above splat.

## CVSS-Vektor

```
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Lokal | good |
| AC Komplexität | Gering | bad |
| PR Privilegien | Gering | warn |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Hoch | bad |

## Patch verfügbar (OSV)

- Kernel ≥ 5.15.163
- Kernel ≥ 6.1.98
- Kernel ≥ 6.6.39
- Kernel ≥ 6.9.9

## Referenzen

- <https://git.kernel.org/stable/c/3325628cb36b7f216c5716e7b5124d9dc81199e4>
- <https://git.kernel.org/stable/c/4c06c13317b9a08decedcd7aaf706691e336277c>
- <https://git.kernel.org/stable/c/55a40406aac555defe9bdd0adec9508116ce7cb1>
- <https://git.kernel.org/stable/c/09e650c3a3a7d804430260510534ccbf71c75b2e>
- <https://git.kernel.org/stable/c/9f6958ba2e902f9820c594869bd710ba74b7c4c0>
- <https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2024-42109) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_