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

In the Linux kernel, the following vulnerability has been resolved: netfilter: nftables: avoid overflows in nft_hash_buckets() Number of buckets being stored

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 ne

Description from the National Vulnerability Database, published by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

What it means for a small business

Linux is on the computers, phones or browsers your team uses every day. Turn on automatic updates and restart: most of these fixes only take effect after a restart.

How likely is an attack? The Exploit Prediction Scoring System, run by FIRST (the global association of security response teams), puts the odds of this one being exploited in the next 30 days at 0.26%, higher than 18% of CVEs. That’s low, but low isn’t zero, and the odds jump the day someone publishes an exploit. Scored October 29, 2026, updated daily.

Check your own setup

Website check: reads what your site runs from the outside (WordPress version, plugins it can see, old server software) and matches it against this database.
Server check: what your web server says about itself, and whether that version has known flaws.

Sources

Part of the Huttenlocher Technologies vulnerability database, refreshed twice a day from CISA and the NVD. The title, category and plain-language guidance are ours; check the linked record before acting on a detail. This is general guidance, not a review of your systems.

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