CVE-2024-42109: Linux kernel · netfilter: nf_tables: unconditionally flush pending work before notifier
Source GCVE Database
Not known to be exploited · CVSS 5.5 Medium.
Data as of 29 Oct 2026, 22:52 UTC
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 30 Jul 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
Description
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.
References
- nvd.nist.gov/vuln/detail/CVE-2024-42109 (opens in a new tab)
- git.kernel.org/stable/c/09e650c3a3a7d804430260510534ccbf71c75b2e (opens in a new tab)
- git.kernel.org/stable/c/3325628cb36b7f216c5716e7b5124d9dc81199e4 (opens in a new tab)
- git.kernel.org/stable/c/4c06c13317b9a08decedcd7aaf706691e336277c (opens in a new tab)
- git.kernel.org/stable/c/55a40406aac555defe9bdd0adec9508116ce7cb1 (opens in a new tab)
- git.kernel.org/stable/c/9f6958ba2e902f9820c594869bd710ba74b7c4c0 (opens in a new tab)
- lists.debian.org/debian-lts-announce/2025/01/msg00001.html (opens in a new tab)