# CVE-2021-46992: linux: In the Linux kernel, the following vulnerability has been resolved:  netfilter: nftables: avoid overflows in nft_hash...

CVE-2021-46992 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-46992, released February 28, 2024. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2021-46992
- Priority: High
- CVSS: 7.1 (high)
- EPSS: 0.0026
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Feb 28, 2024

## Description

In the Linux kernel, the following vulnerability has been resolved:  netfilter: nftables: avoid overflows in nft_hash_buckets()  Number of buckets being stored in 32bit variables, we have to ensure that no overflows occur in nft_hash_buckets()  syzbot injected a size == 0x40000000 and reported:  UBSAN: shift-out-of-bounds in ./include/linux/log2.h:57:13 shift exponent 64 is too large for 64-bit type 'long unsigned int' CPU: 1 PID: 29539 Comm: syz-executor.4 Not tainted 5.12.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace:  __dump_stack lib/dump_stack.c:79 [inline]  dump_stack+0x141/0x1d7 lib/dump_stack.c:120  ubsan_epilogue+0xb/0x5a lib/ubsan.c:148  __ubsan_handle_shift_out_of_bounds.cold+0xb1/0x181 lib/ubsan.c:327  __roundup_pow_of_two include/linux/log2.h:57 [inline]  nft_hash_buckets net/netfilter/nft_set_hash.c:411 [inline]  nft_hash_estimate.cold+0x19/0x1e net/netfilter/nft_set_hash.c:652  nft_select_set_ops net/netfilter/nf_tables_api.c:3586 [inline]  nf_tables_newset+0xe62/0x3110 net/netfilter/nf_tables_api.c:4322  nfnetlink_rcv_batch+0xa09/0x24b0 net/netfilter/nfnetlink.c:488  nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:612 [inline]  nfnetlink_rcv+0x3af/0x420 net/netfilter/nfnetlink.c:630  netlink_unicast_kernel net/netlink/af_netlink.c:1312 [inline]  netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1338  netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1927  sock_sendmsg_nosec net/socket.c:654 [inline]  sock_sendmsg+0xcf/0x120 net/socket.c:674  ____sys_sendmsg+0x6e8/0x810 net/socket.c:2350  ___sys_sendmsg+0xf3/0x170 net/socket.c:2404  __sys_sendmsg+0xe5/0x1b0 net/socket.c:2433  do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 5.10.38-1 | [DEBIAN-CVE-2021-46992](https://patchblox.com/security/data/fix/linux/debian-cve-2021-46992.md) | Feb 28, 2024 |
| Linux | linux Debian 13.5 (trixie) | 5.10.38-1 | [DEBIAN-CVE-2021-46992](https://patchblox.com/security/data/fix/linux/debian-cve-2021-46992.md) | Feb 28, 2024 |
| Linux | linux Debian 14 | 5.10.38-1 | [DEBIAN-CVE-2021-46992](https://patchblox.com/security/data/fix/linux/debian-cve-2021-46992.md) | Feb 28, 2024 |

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