CVE-2021-45486

LOWNVD 3.53.5—

3.5

In the IPv4 implementation in the Linux kernel before 5.12.4, net/ipv4/route.c has an information leak because the hash table is very small.

CVSS v3: 3.5
EG Score: 3.5(medium)
EPSS: 23.1%
KEV: Not listed

Published

December 25, 2021

Last Modified

November 21, 2024

References (8)

cve@mitrehttps://arxiv.org/pdf/2112.09604.pdf
cve@mitrehttps://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.12.4
cve@mitrehttps://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/net/ipv4/route.c?id=aa6dd211e4b1dde9d5dc25d699d35f789ae7eeba
cve@mitrehttps://www.oracle.com/security-alerts/cpujul2022.html
af854a3a-2127-422b-91ae-364da2661108https://arxiv.org/pdf/2112.09604.pdf
af854a3a-2127-422b-91ae-364da2661108https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.12.4
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/net/ipv4/route.c?id=aa6dd211e4b1dde9d5dc25d699d35f789ae7eeba
af854a3a-2127-422b-91ae-364da2661108https://www.oracle.com/security-alerts/cpujul2022.html

Patch Availability(5)

Vendor / Ecosystem	Fixed in / Patch	Released	Source
ubuntu	linux-image-virtual-lts-xenial (4.4.0.223.194) @ trusty	2026-05-26	ubuntu
redhat	kernel-rt-0:4.18.0-305.65.1.rt7.137.el8_4	2022-10-18	redhat
redhat	kernel-0:4.18.0-305.65.1.el8_4	2022-10-18	redhat
redhat	kernel-rt-0:4.18.0-372.9.1.rt7.166.el8	2022-05-10	redhat
redhat	kernel-0:4.18.0-372.9.1.el8	2022-05-10	redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

CWE-327Use of a Broken or Risky Cryptographic Algorithm

All Vendor Advisories

(6)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 11× in last 7d / 20× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

2026-06-08 14:15 UTCEPSS rescore
2026-06-08 14:15 UTCEPSS rescore
2026-06-07 15:23 UTCEPSS rescore
2026-06-07 15:23 UTCEPSS rescore
2026-06-06 13:46 UTCEPSS rescore
2026-06-06 13:46 UTCEPSS rescore
2026-06-05 22:45 UTCEPSS rescore
2026-06-05 06:09 UTCEPSS rescore
2026-06-05 06:09 UTCEPSS rescore
2026-06-04 13:10 UTCEPSS rescore
2026-06-04 13:10 UTCEPSS rescore
2026-06-02 20:11 UTCEPSS rescore
2026-06-02 20:11 UTCEPSS rescore
2026-06-01 13:50 UTCEPSS rescore
2026-06-01 13:50 UTCEPSS rescore
2026-05-31 22:29 UTCEPSS rescore
2026-05-31 22:29 UTCEPSS rescore
2026-05-31 00:15 UTCEPSS rescore
2026-05-31 00:15 UTCEPSS rescore
2026-05-29 13:42 UTCEPSS rescore

Frequently asked(5)

What is CVE-2021-45486?

CVE-2021-45486 is a low vulnerability published on December 25, 2021. In the IPv4 implementation in the Linux kernel before 5.12.4, net/ipv4/route.c has an information leak because the hash table is very small.

When was CVE-2021-45486 disclosed?

CVE-2021-45486 was first published in the National Vulnerability Database on December 25, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2021-45486 actively exploited?

CVE-2021-45486 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 23.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-45486?

CVE-2021-45486 has a CVSS v3 base score of 3.5 (NVD).

How do I remediate CVE-2021-45486?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-45486, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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CVE-2021-45486

Published

Last Modified

References (8)

Patch Availability(5)

Weakness Classification(1)

All Vendor Advisories

Data Freshness Timeline

Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-45486?

Same vendor

Same CWE

CVE-2021-45486

📅 Published

🔄 Last Modified

🔗 References (8)

Patch Availability(5)

Weakness Classification(1)

All Vendor Advisories

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-45486?

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Frequently asked(5)

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