Skip to content
Fencer Intel
medium 5.5

CVE-2021-46915 json

netfilter: nft_limit: avoid possible divide error in nft_limit_init

published 2y ago modified 4mo ago also EUVD-2021-33563

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 15%
public exploits
0
none known

Summary

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

netfilter: nft_limit: avoid possible divide error in nft_limit_init

div_u64() divides u64 by u32.

nft_limit_init() wants to divide u64 by u64, use the appropriate math function (div64_u64)

divide error: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 8390 Comm: syz-executor188 Not tainted 5.12.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:div_u64_rem include/linux/math64.h:28 [inline] RIP: 0010:div_u64 include/linux/math64.h:127 [inline] RIP: 0010:nft_limit_init+0x2a2/0x5e0 net/netfilter/nft_limit.c:85 Code: ef 4c 01 eb 41 0f 92 c7 48 89 de e8 38 a5 22 fa 4d 85 ff 0f 85 97 02 00 00 e8 ea 9e 22 fa 4c 0f af f3 45 89 ed 31 d2 4c 89 f0 <49> f7 f5 49 89 c6 e8 d3 9e 22 fa 48 8d 7d 48 48 b8 00 00 00 00 00 RSP: 0018:ffffc90009447198 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000200000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff875152e6 RDI: 0000000000000003 RBP: ffff888020f80908 R08: 0000200000000000 R09: 0000000000000000 R10: ffffffff875152d8 R11: 0000000000000000 R12: ffffc90009447270 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 000000000097a300(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000200001c4 CR3: 0000000026a52000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: nf_tables_newexpr net/netfilter/nf_tables_api.c:2675 [inline] nft_expr_init+0x145/0x2d0 net/netfilter/nf_tables_api.c:2713 nft_set_elem_expr_alloc+0x27/0x280 net/netfilter/nf_tables_api.c:5160 nf_tables_newset+0x1997/0x3150 net/netfilter/nf_tables_api.c:4321 nfnetlink_rcv_batch+0x85a/0x21b0 net/netfilter/nfnetlink.c:456 nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:580 [inline] nfnetlink_rcv+0x3af/0x420 net/netfilter/nfnetlink.c:598 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 entry_SYSCALL_64_after_hwframe+0x44/0xae

Patch / fix

  • Linux Linux 4.14.232, 4.19.189, 5.4.114, 5.10.32, 5.11.16, 5.12
  • linux Debian 14, Debian 13, Debian 12 5.10.38-1

debian advisories DEBIAN-CVE-2021-46915

  • linux Ubuntu 18.04 LTS 4.15.0-147.151
  • linux Ubuntu 20.04 LTS 5.4.0-74.83
  • linux-aws Ubuntu 18.04 LTS 4.15.0-1106.113
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1049.51
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1044.47
  • linux-kvm Ubuntu 18.04 LTS 4.15.0-1094.96
  • linux-kvm Ubuntu 20.04 LTS 5.4.0-1040.41
  • linux-azure Ubuntu 20.04 LTS 5.4.0-1048.50

ubuntu advisories UBUNTU-CVE-2021-46915

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel-rt RHEL 8.4 TUS 4.18.0-305.130.1.rt7.206.el8_4
  • kernel-rt-kvm RHEL 8.4 TUS 4.18.0-305.130.1.rt7.206.el8_4
  • kernel-rt-core RHEL 8.4 TUS 4.18.0-305.130.1.rt7.206.el8_4
  • kernel-rt-modules RHEL 8.4 TUS 4.18.0-305.130.1.rt7.206.el8_4
  • kernel-rt-debug-kvm RHEL 8.4 TUS 4.18.0-305.130.1.rt7.206.el8_4
  • kernel-rt-debug-core RHEL 8.4 TUS 4.18.0-305.130.1.rt7.206.el8_4
  • kernel-rt-debug-modules RHEL 8.4 TUS 4.18.0-305.130.1.rt7.206.el8_4
  • kernel-rt-modules-extra RHEL 8.4 TUS 4.18.0-305.130.1.rt7.206.el8_4

red hat advisories RHSA-2024:2585RHSA-2024:2582RHSA-2024:2008RHSA-2024:2006

  • kernel-rt SLE Real Time 12 SP5 4.12.14-10.171.1
  • kernel-syms-rt SLE Real Time 12 SP5 4.12.14-10.171.1
  • kernel-rt_debug SLE Real Time 12 SP5 4.12.14-10.171.1
  • kernel-source-rt SLE Real Time 12 SP5 4.12.14-10.171.1
  • kernel-azure SLES for SAP 12 SP5, SLES 12 SP5 4.12.14-16.173.1
  • kernel-syms-azure SLES for SAP 12 SP5, SLES 12 SP5 4.12.14-16.173.1
  • kernel-source-azure SLES for SAP 12 SP5, SLES 12 SP5 4.12.14-16.173.1
  • kernel-default SLES for SAP 15 SP2, SLES 15 SP2-LTSS, SLE Live Patching 15 SP2 +2 more 5.3.18-150200.24.183.1

suse advisories SUSE-SU-2024:0976-1SUSE-SU-2024:0975-1SUSE-SU-2024:0926-1SUSE-SU-2024:0925-1SUSE-SU-2024:0857-1SUSE-SU-2024:0856-1

Is CVE-2021-46915 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-46915 updated cvss 5.5

kernel: netfilter: divide error in nft_limit_init

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux BaseOS AUS (v. 8.2) perf 4.18.0-193.133.1.el8_2, kernel 4.18.0-193.133.1.el8_2, bpftool 4.18.0-193.133.1.el8_2, kernel-core 4.18.0-193.133.1.el8_2, kernel-tools 4.18.0-193.133.1.el8_2, python3-perf 4.18.0-193.133.1.el8_2, +8 more
    fixed: vendor fix RHSA-2024:2006
  • Red Hat Enterprise Linux BaseOS AUS (v.8.4) perf 4.18.0-305.130.1.el8_4, kernel 4.18.0-305.130.1.el8_4, bpftool 4.18.0-305.130.1.el8_4, kernel-core 4.18.0-305.130.1.el8_4, kernel-tools 4.18.0-305.130.1.el8_4, python3-perf 4.18.0-305.130.1.el8_4, +8 more
    fixed: vendor fix RHSA-2024:2582
  • Red Hat Enterprise Linux BaseOS E4S (v. 8.2) perf 4.18.0-193.133.1.el8_2, kernel 4.18.0-193.133.1.el8_2, bpftool 4.18.0-193.133.1.el8_2, kernel-core 4.18.0-193.133.1.el8_2, kernel-tools 4.18.0-193.133.1.el8_2, python3-perf 4.18.0-193.133.1.el8_2, +9 more
    fixed: vendor fix RHSA-2024:2006
  • Red Hat Enterprise Linux BaseOS E4S (v.8.4) perf 4.18.0-305.130.1.el8_4, kernel 4.18.0-305.130.1.el8_4, bpftool 4.18.0-305.130.1.el8_4, kernel-core 4.18.0-305.130.1.el8_4, kernel-tools 4.18.0-305.130.1.el8_4, python3-perf 4.18.0-305.130.1.el8_4, +9 more
    fixed: vendor fix RHSA-2024:2582
  • Red Hat Enterprise Linux BaseOS TUS (v. 8.2) perf 4.18.0-193.133.1.el8_2, kernel 4.18.0-193.133.1.el8_2, bpftool 4.18.0-193.133.1.el8_2, kernel-core 4.18.0-193.133.1.el8_2, kernel-tools 4.18.0-193.133.1.el8_2, python3-perf 4.18.0-193.133.1.el8_2, +8 more
    fixed: vendor fix RHSA-2024:2006
  • Red Hat Enterprise Linux BaseOS TUS (v.8.4) perf 4.18.0-305.130.1.el8_4, kernel 4.18.0-305.130.1.el8_4, bpftool 4.18.0-305.130.1.el8_4, kernel-core 4.18.0-305.130.1.el8_4, kernel-tools 4.18.0-305.130.1.el8_4, python3-perf 4.18.0-305.130.1.el8_4, +8 more
    fixed: vendor fix RHSA-2024:2582
show 4 more
  • Red Hat Enterprise Linux NFV TUS (v.8.4) kernel-rt 4.18.0-305.130.1.rt7.206.el8_4, kernel-rt-kvm 4.18.0-305.130.1.rt7.206.el8_4, kernel-rt-core 4.18.0-305.130.1.rt7.206.el8_4, kernel-rt-modules 4.18.0-305.130.1.rt7.206.el8_4, kernel-rt-debug-kvm 4.18.0-305.130.1.rt7.206.el8_4, kernel-rt-debug-core 4.18.0-305.130.1.rt7.206.el8_4, +4 more
    fixed: vendor fix RHSA-2024:2585
  • Red Hat Enterprise Linux Real Time for NFV TUS (v. 8.2) kernel-rt 4.18.0-193.133.1.rt13.184.el8_2, kernel-rt-kvm 4.18.0-193.133.1.rt13.184.el8_2, kernel-rt-core 4.18.0-193.133.1.rt13.184.el8_2, kernel-rt-modules 4.18.0-193.133.1.rt13.184.el8_2, kernel-rt-debug-kvm 4.18.0-193.133.1.rt13.184.el8_2, kernel-rt-debug-core 4.18.0-193.133.1.rt13.184.el8_2, +4 more Red Hat Enterprise Linux Real Time TUS (v. 8.2) kernel-rt 4.18.0-193.133.1.rt13.184.el8_2, kernel-rt-core 4.18.0-193.133.1.rt13.184.el8_2, kernel-rt-modules 4.18.0-193.133.1.rt13.184.el8_2, kernel-rt-debug-core 4.18.0-193.133.1.rt13.184.el8_2, kernel-rt-debug-modules 4.18.0-193.133.1.rt13.184.el8_2, kernel-rt-modules-extra 4.18.0-193.133.1.rt13.184.el8_2, +2 more
    fixed: vendor fix RHSA-2024:2008
  • Red Hat Enterprise Linux RT TUS (v.8.4) kernel-rt 4.18.0-305.130.1.rt7.206.el8_4, kernel-rt-core 4.18.0-305.130.1.rt7.206.el8_4, kernel-rt-modules 4.18.0-305.130.1.rt7.206.el8_4, kernel-rt-debug-core 4.18.0-305.130.1.rt7.206.el8_4, kernel-rt-debug-modules 4.18.0-305.130.1.rt7.206.el8_4, kernel-rt-modules-extra 4.18.0-305.130.1.rt7.206.el8_4, +2 more
    fixed: vendor fix RHSA-2024:2585
  • Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2y ago

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 15% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

Classification

Weakness
Technology feeds

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.