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NVD / CVE Program· CNA Linux

CVE-2021-46915: netfilter: nft_limit: avoid possible divide error in nft_limit_init

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.24% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 01fb1626b620cb37a65ad08e0f626489e8f042ef, 1bb3ee4259936cc3b2d80a4a480bbb4868575071, 9065ccb9ec92c5120e7e97958397ebdb454f23d6.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 01fb1626b620cb37a65ad08e0f626489e8f042ef, 1bb3ee4259936cc3b2d80a4a480bbb4868575071, 9065ccb9ec92c5120e7e97958397ebdb454f23d6 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Feb 27, 2024
Updated
Jun 17, 2026
EPSS
0.2% · 15th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2021-46915

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel4.13.0 and later · before 4.14.232
  • linux linux kernel4.15.0 and later · before 4.19.189
  • linux linux kernel4.20.0 and later · before 5.4.114
  • linux linux kernel5.5.0 and later · before 5.10.32
  • linux linux kernel5.11.0 and later · before 5.11.16

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 4.13affected
    • c26844eda9d4fdbd266660e3b3de2d0270e3a1ed and later · before 9065ccb9ec92c5120e7e97958397ebdb454f23d6affected · git
    • c26844eda9d4fdbd266660e3b3de2d0270e3a1ed and later · before fadd3c4afdf3d4c21f4d138502f8b76334987e26affected · git
    • c26844eda9d4fdbd266660e3b3de2d0270e3a1ed and later · before 01fb1626b620cb37a65ad08e0f626489e8f042efaffected · git
    • c26844eda9d4fdbd266660e3b3de2d0270e3a1ed and later · before dc1732baa9da5b68621586bf8636ebbc27dc62d2affected · git
    • c26844eda9d4fdbd266660e3b3de2d0270e3a1ed and later · before 1bb3ee4259936cc3b2d80a4a480bbb4868575071affected · git
    • c26844eda9d4fdbd266660e3b3de2d0270e3a1ed and later · before b895bdf5d643b6feb7c60856326dd4feb6981560affected · git
    • before 4.13not affected · semver
    • 4.14.232 and later · up to and including 4.14.*not affected · semver
    • 4.19.189 and later · up to and including 4.19.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 5.10.38-15.10.38-1
Red Hat:rhel_aus:8.2::baseosbpftoolbefore 0:4.18.0-193.133.1.el8_20:4.18.0-193.133.1.el8_2
Red Hat:rhel_aus:8.2::baseosbpftool-debuginfobefore 0:4.18.0-193.133.1.el8_20:4.18.0-193.133.1.el8_2
Red Hat:rhel_aus:8.2::baseoskernelbefore 0:4.18.0-193.133.1.el8_20:4.18.0-193.133.1.el8_2
Red Hat:rhel_aus:8.2::baseoskernel-abi-whitelistsbefore 0:4.18.0-193.133.1.el8_20:4.18.0-193.133.1.el8_2
Red Hat:rhel_aus:8.2::baseoskernel-corebefore 0:4.18.0-193.133.1.el8_20:4.18.0-193.133.1.el8_2
Red Hat:rhel_aus:8.2::baseoskernel-debugbefore 0:4.18.0-193.133.1.el8_20:4.18.0-193.133.1.el8_2
Red Hat:rhel_aus:8.2::baseoskernel-debug-corebefore 0:4.18.0-193.133.1.el8_20:4.18.0-193.133.1.el8_2
Red Hat:rhel_aus:8.2::baseoskernel-debug-debuginfobefore 0:4.18.0-193.133.1.el8_20:4.18.0-193.133.1.el8_2
Red Hat:rhel_aus:8.2::baseoskernel-debug-develbefore 0:4.18.0-193.133.1.el8_20:4.18.0-193.133.1.el8_2
Red Hat:rhel_aus:8.2::baseoskernel-debug-modulesbefore 0:4.18.0-193.133.1.el8_20:4.18.0-193.133.1.el8_2
Red Hat:rhel_aus:8.2::baseoskernel-debug-modules-extrabefore 0:4.18.0-193.133.1.el8_20:4.18.0-193.133.1.el8_2
Red Hat:rhel_aus:8.2::baseoskernel-debuginfobefore 0:4.18.0-193.133.1.el8_20:4.18.0-193.133.1.el8_2
Red Hat:rhel_aus:8.2::baseoskernel-debuginfo-common-x86_64before 0:4.18.0-193.133.1.el8_20:4.18.0-193.133.1.el8_2
Red Hat:rhel_aus:8.2::baseoskernel-develbefore 0:4.18.0-193.133.1.el8_20:4.18.0-193.133.1.el8_2
Red Hat:rhel_aus:8.2::baseoskernel-docbefore 0:4.18.0-193.133.1.el8_20:4.18.0-193.133.1.el8_2
Red Hat:rhel_aus:8.2::baseoskernel-modulesbefore 0:4.18.0-193.133.1.el8_20:4.18.0-193.133.1.el8_2
Red Hat:rhel_aus:8.2::baseoskernel-modules-extrabefore 0:4.18.0-193.133.1.el8_20:4.18.0-193.133.1.el8_2
Red Hat:rhel_aus:8.2::baseoskernel-toolsbefore 0:4.18.0-193.133.1.el8_20:4.18.0-193.133.1.el8_2
Red Hat:rhel_aus:8.2::baseoskernel-tools-debuginfobefore 0:4.18.0-193.133.1.el8_20:4.18.0-193.133.1.el8_2
Red Hat:rhel_aus:8.2::baseoskernel-tools-libsbefore 0:4.18.0-193.133.1.el8_20:4.18.0-193.133.1.el8_2
Red Hat:rhel_aus:8.2::baseosperfbefore 0:4.18.0-193.133.1.el8_20:4.18.0-193.133.1.el8_2
Red Hat:rhel_aus:8.2::baseosperf-debuginfobefore 0:4.18.0-193.133.1.el8_20:4.18.0-193.133.1.el8_2
Red Hat:rhel_aus:8.2::baseospython3-perfbefore 0:4.18.0-193.133.1.el8_20:4.18.0-193.133.1.el8_2

+90

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2021-46913Feb 27, 2024 · netfilter: nftables: clone set element expression template
    22Monitor
  • ← EarlierCVE-2021-46914Feb 27, 2024 · ixgbe: fix unbalanced device enable/disable in suspend/resume
    22Monitor
  • Later →CVE-2021-46916Feb 27, 2024 · ixgbe: Fix NULL pointer dereference in ethtool loopback test
    22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux01fb1626b620cb37a65ad08e0f626489e8f042efVendor (CNA)
Linux Linux1bb3ee4259936cc3b2d80a4a480bbb4868575071Vendor (CNA)
Linux Linux9065ccb9ec92c5120e7e97958397ebdb454f23d6Vendor (CNA)
Linux Linuxb895bdf5d643b6feb7c60856326dd4feb6981560Vendor (CNA)
Linux Linuxdc1732baa9da5b68621586bf8636ebbc27dc62d2Vendor (CNA)
Linux Linuxfadd3c4afdf3d4c21f4d138502f8b76334987e26Vendor (CNA)
debian:linux5.10.38-1 · Debian:12Package registry (OSV)
red hat:bpftool0:4.18.0-193.133.1.el8_2 · Red Hat:rhel_aus:8.2::baseosPackage registry (OSV)
red hat:bpftool-debuginfo0:4.18.0-193.133.1.el8_2 · Red Hat:rhel_aus:8.2::baseosPackage registry (OSV)
red hat:kernel0:4.18.0-193.133.1.el8_2 · Red Hat:rhel_aus:8.2::baseosPackage registry (OSV)
red hat:kernel-abi-whitelists0:4.18.0-193.133.1.el8_2 · Red Hat:rhel_aus:8.2::baseosPackage registry (OSV)
red hat:kernel-core0:4.18.0-193.133.1.el8_2 · Red Hat:rhel_aus:8.2::baseosPackage registry (OSV)
red hat:kernel-debug0:4.18.0-193.133.1.el8_2 · Red Hat:rhel_aus:8.2::baseosPackage registry (OSV)
red hat:kernel-debug-core0:4.18.0-193.133.1.el8_2 · Red Hat:rhel_aus:8.2::baseosPackage registry (OSV)
red hat:kernel-debug-debuginfo0:4.18.0-193.133.1.el8_2 · Red Hat:rhel_aus:8.2::baseosPackage registry (OSV)
red hat:kernel-debug-devel0:4.18.0-193.133.1.el8_2 · Red Hat:rhel_aus:8.2::baseosPackage registry (OSV)
red hat:kernel-debug-modules0:4.18.0-193.133.1.el8_2 · Red Hat:rhel_aus:8.2::baseosPackage registry (OSV)
red hat:kernel-debug-modules-extra0:4.18.0-193.133.1.el8_2 · Red Hat:rhel_aus:8.2::baseosPackage registry (OSV)
red hat:kernel-debuginfo0:4.18.0-193.133.1.el8_2 · Red Hat:rhel_aus:8.2::baseosPackage registry (OSV)
suse:kernel-64kb5.3.18-150300.59.153.2 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSPackage registry (OSV)
suse:kernel-default5.3.18-150300.59.153.2 · SUSE:Linux Enterprise Live Patching 15 SP3Package registry (OSV)
suse:kernel-default-base5.3.18-150300.59.153.2.150300.18.90.2 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSPackage registry (OSV)
suse:kernel-docs5.3.18-150300.59.153.2 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSPackage registry (OSV)
suse:kernel-livepatch-SLE15-SP3_Update_421-150300.7.3.2 · SUSE:Linux Enterprise Live Patching 15 SP3Package registry (OSV)
suse:kernel-obs-build5.3.18-150300.59.153.2 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSPackage registry (OSV)
suse:kernel-preempt5.3.18-150300.59.153.2 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSPackage registry (OSV)
suse:kernel-rt5.3.18-150300.161.1 · SUSE:Linux Enterprise Micro 5.1Package registry (OSV)
suse:kernel-source5.3.18-150300.59.153.2 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSPackage registry (OSV)
suse:kernel-source-rt5.3.18-150300.161.1 · SUSE:Linux Enterprise Micro 5.1Package registry (OSV)
suse:kernel-syms5.3.18-150300.59.153.1 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSPackage registry (OSV)

+1

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2024-2694564 days apartcrypto: iaa - Fix nr_cpus < nr_iaa case
    33Monitor
  • CVE-2021-470803 days apartRDMA/core: Prevent divide-by-zero error triggered by the user
    22Monitor
  • CVE-2024-2677436 days apartext4: avoid dividing by 0 in mb_update_avg_fragment_size() when block bitmap corrupt
    22Monitor
  • CVE-2024-2677736 days apartfbdev: sis: Error out if pixclock equals zero
    22Monitor
  • CVE-2024-2677836 days apartfbdev: savage: Error out if pixclock equals zero
    22Monitor
  • CVE-2024-2705964 days apartUSB: usb-storage: Prevent divide-by-0 error in isd200_ata_command
    22Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-369 · Divide By Zero

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (5 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records