CVE-2025-22056 netfilter: nft_tunnel: fix geneve_opt type confusion addition
A type confusion error in the Linux kernel netfilter tunnel module allows heap out-of-bounds writes, potentially leading to code execution or privilege escalation.
- 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-2025-22056?
CVE-2025-22056 is a high-severity memory corruption vulnerability in Linux kernel, published on 16 Apr 2025. 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: nft_tunnel: fix geneve_opt type confusion addition
When handling multiple NFTA_TUNNEL_KEY_OPTS_GENEVE attributes, the parsing logic should place every geneve_opt structure one by one compactly. Hence, when deciding the next geneve_opt position, the pointer addition should be in units of char *.
However, the current implementation erroneously does type conversion before the addition, which will lead to heap out-of-bounds write.
[ 6.989857] ================================================================== [ 6.990293] BUG: KASAN: slab-out-of-bounds in nft_tunnel_obj_init+0x977/0xa70 [ 6.990725] Write of size 124 at addr ffff888005f18974 by task poc/178 [ 6.991162] [ 6.991259] CPU: 0 PID: 178 Comm: poc-oob-write Not tainted 6.1.132 #1 [ 6.991655] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 [ 6.992281] Call Trace: [ 6.992423] <TASK> [ 6.992586] dump_stack_lvl+0x44/0x5c [ 6.992801] print_report+0x184/0x4be [ 6.993790] kasan_report+0xc5/0x100 [ 6.994252] kasan_check_range+0xf3/0x1a0 [ 6.994486] memcpy+0x38/0x60 [ 6.994692] nft_tunnel_obj_init+0x977/0xa70 [ 6.995677] nft_obj_init+0x10c/0x1b0 [ 6.995891] nf_tables_newobj+0x585/0x950 [ 6.996922] nfnetlink_rcv_batch+0xdf9/0x1020 [ 6.998997] nfnetlink_rcv+0x1df/0x220 [ 6.999537] netlink_unicast+0x395/0x530 [ 7.000771] netlink_sendmsg+0x3d0/0x6d0 [ 7.001462] __sock_sendmsg+0x99/0xa0 [ 7.001707] ____sys_sendmsg+0x409/0x450 [ 7.002391] ___sys_sendmsg+0xfd/0x170 [ 7.003145] __sys_sendmsg+0xea/0x170 [ 7.004359] do_syscall_64+0x5e/0x90 [ 7.005817] entry_SYSCALL_64_after_hwframe+0x6e/0xd8 [ 7.006127] RIP: 0033:0x7ec756d4e407 [ 7.006339] Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 faf [ 7.007364] RSP: 002b:00007ffed5d46760 EFLAGS: 00000202 ORIG_RAX: 000000000000002e [ 7.007827] RAX: ffffffffffffffda RBX: 00007ec756cc4740 RCX: 00007ec756d4e407 [ 7.008223] RDX: 0000000000000000 RSI: 00007ffed5d467f0 RDI: 0000000000000003 [ 7.008620] RBP: 00007ffed5d468a0 R08: 0000000000000000 R09: 0000000000000000 [ 7.009039] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 [ 7.009429] R13: 00007ffed5d478b0 R14: 00007ec756ee5000 R15: 00005cbd4e655cb8
Fix this bug with correct pointer addition and conversion in parse and dump code.
Weakness: CWE-787
Which versions are affected by CVE-2025-22056?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-22056?
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-2025-22056 being exploited?
There is no known exploitation of CVE-2025-22056 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-61463, BELL-CVE-2025-22056, DEBIAN-CVE-2025-22056, GHSA-7mx5-64fm-676w, ROOT-OS-UBUNTU-2404-CVE-2025-22056, UBUNTU-CVE-2025-22056.