CVE-2024-27012 netfilter: nf_tables: restore set elements when delete set fails

High 7.8 Published 1 May 2024 Updated 5 Aug 2026

A memory leak in the Linux kernel netfilter subsystem can lead to resource exhaustion and denial of service when set deletion fails.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Local or same network only
Victim action needed: Not needed
Fix: Available

What is CVE-2024-27012?

CVE-2024-27012 is a high-severity memory corruption vulnerability in Fedoraproject Fedora, published on 1 May 2024. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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

netfilter: nf_tables: restore set elements when delete set fails

From abort path, nft_mapelem_activate() needs to restore refcounters to the original state. Currently, it uses the set->ops->walk() to iterate over these set elements. The existing set iterator skips inactive elements in the next generation, this does not work from the abort path to restore the original state since it has to skip active elements instead (not inactive ones).

This patch moves the check for inactive elements to the set iterator callback, then it reverses the logic for the .activate case which needs to skip active elements.

Toggle next generation bit for elements when delete set command is invoked and call nft_clear() from .activate (abort) path to restore the next generation bit.

The splat below shows an object in mappings memleak:

[43929.457523] ------------[ cut here ]------------ [43929.457532] WARNING: CPU: 0 PID: 1139 at include/net/netfilter/nf_tables.h:1237 nft_setelem_data_deactivate+0xe4/0xf0 [nf_tables] [...] [43929.458014] RIP: 0010:nft_setelem_data_deactivate+0xe4/0xf0 [nf_tables] [43929.458076] Code: 83 f8 01 77 ab 49 8d 7c 24 08 e8 37 5e d0 de 49 8b 6c 24 08 48 8d 7d 50 e8 e9 5c d0 de 8b 45 50 8d 50 ff 89 55 50 85 c0 75 86 <0f> 0b eb 82 0f 0b eb b3 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 [43929.458081] RSP: 0018:ffff888140f9f4b0 EFLAGS: 00010246 [43929.458086] RAX: 0000000000000000 RBX: ffff8881434f5288 RCX: dffffc0000000000 [43929.458090] RDX: 00000000ffffffff RSI: ffffffffa26d28a7 RDI: ffff88810ecc9550 [43929.458093] RBP: ffff88810ecc9500 R08: 0000000000000001 R09: ffffed10281f3e8f [43929.458096] R10: 0000000000000003 R11: ffff0000ffff0000 R12: ffff8881434f52a0 [43929.458100] R13: ffff888140f9f5f4 R14: ffff888151c7a800 R15: 0000000000000002 [43929.458103] FS: 00007f0c687c4740(0000) GS:ffff888390800000(0000) knlGS:0000000000000000 [43929.458107] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [43929.458111] CR2: 00007f58dbe5b008 CR3: 0000000123602005 CR4: 00000000001706f0 [43929.458114] Call Trace: [43929.458118] <TASK> [43929.458121] ? __warn+0x9f/0x1a0 [43929.458127] ? nft_setelem_data_deactivate+0xe4/0xf0 [nf_tables] [43929.458188] ? report_bug+0x1b1/0x1e0 [43929.458196] ? handle_bug+0x3c/0x70 [43929.458200] ? exc_invalid_op+0x17/0x40 [43929.458211] ? nft_setelem_data_deactivate+0xd7/0xf0 [nf_tables] [43929.458271] ? nft_setelem_data_deactivate+0xe4/0xf0 [nf_tables] [43929.458332] nft_mapelem_deactivate+0x24/0x30 [nf_tables] [43929.458392] nft_rhash_walk+0xdd/0x180 [nf_tables] [43929.458453] ? __pfx_nft_rhash_walk+0x10/0x10 [nf_tables] [43929.458512] ? rb_insert_color+0x2e/0x280 [43929.458520] nft_map_deactivate+0xdc/0x1e0 [nf_tables] [43929.458582] ? __pfx_nft_map_deactivate+0x10/0x10 [nf_tables] [43929.458642] ? __pfx_nft_mapelem_deactivate+0x10/0x10 [nf_tables] [43929.458701] ? __rcu_read_unlock+0x46/0x70 [43929.458709] nft_delset+0xff/0x110 [nf_tables] [43929.458769] nft_flush_table+0x16f/0x460 [nf_tables] [43929.458830] nf_tables_deltable+0x501/0x580 [nf_tables]

Weakness: CWE-401

Which versions are affected by CVE-2024-27012?

It affects 2 products.

Products include Fedoraproject Fedora, Linux kernel.

How do I fix CVE-2024-27012?

Apply the vendor's patch.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2024-27012 being exploited?

There is no known exploitation of CVE-2024-27012 in the wild and no public exploit code.

All Fedoraproject Fedora vulnerabilities

Sources

Also known as AZL-42195, BELL-CVE-2024-27012, DEBIAN-CVE-2024-27012, GHSA-9r2w-3mr4-v6gq, ROOT-OS-DEBIAN-11-CVE-2024-27012, ROOT-OS-DEBIAN-12-CVE-2024-27012 and 1 more.