CVE-2021-3347

HIGHNVD 7.87.8—Elevated

7.8

An issue was discovered in the Linux kernel through 5.10.11. PI futexes have a kernel stack use-after-free during fault handling, allowing local users to execute code in the kernel, aka CID-34b1a1ce1458.

CVSS v3: 7.8
EG Score: 7.8(medium)
EPSS: 42.0%
KEV: Not listed

Published

January 29, 2021

Last Modified

February 25, 2026

References (38)

Patch Availability(19)

Vendor / Ecosystem	Fixed in / Patch	Released	Source
ubuntu	linux-image-virtual-hwe-20.04-edge (5.8.0.49.54) @ groovy	2026-05-26	ubuntu
ubuntu	linux-image-oracle (4.15.0.1069.57) @ xenial	2026-05-26	ubuntu
ubuntu	linux-image-virtual-hwe-18.04-edge (5.4.0.67.70) @ focal	2026-05-26	ubuntu
ubuntu	linux-image-oem-20.04b (5.10.0.1017.18) @ focal	2026-05-26	ubuntu
redhat	kpatch-patch	2021-09-14	redhat
redhat	kernel-0:3.10.0-1062.56.1.el7	2021-09-14	redhat
redhat	kernel-0:3.10.0-327.100.1.el7	2021-08-31	redhat
redhat	kernel-0:3.10.0-693.90.2.el7	2021-07-20	redhat
redhat	kernel-0:3.10.0-957.78.2.el7	2021-07-20	redhat
redhat	kernel-0:2.6.32-754.41.2.el6	2021-07-20	redhat
redhat	kernel-0:3.10.0-514.90.2.el7	2021-07-20	redhat
redhat	kernel-0:3.10.0-1160.31.1.el7	2021-06-08	redhat
redhat	kernel-rt-0:3.10.0-1160.31.1.rt56.1169.el7	2021-06-08	redhat
redhat	kernel-0:4.18.0-147.48.1.el8_1	2021-05-25	redhat
redhat	kernel-alt-0:4.14.0-115.36.1.el7a	2021-04-27	redhat
redhat	kernel-0:4.18.0-193.51.1.el8_2	2021-04-20	redhat
redhat	kernel-rt-0:4.18.0-193.51.1.rt13.101.el8_2	2021-04-20	redhat
redhat	kernel-0:4.18.0-240.22.1.el8_3	2021-04-06	redhat
redhat	kernel-rt-0:4.18.0-240.22.1.rt7.77.el8_3	2021-04-06	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-416Use After Free

All Vendor Advisories

(24)

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-2021-3347?

CVE-2021-3347 is a high vulnerability published on January 29, 2021. An issue was discovered in the Linux kernel through 5.10.11. PI futexes have a kernel stack use-after-free during fault handling, allowing local users to execute code in the kernel, aka CID-34b1a1ce1458.

When was CVE-2021-3347 disclosed?

CVE-2021-3347 was first published in the National Vulnerability Database on January 29, 2021, with the most recent update on February 25, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2021-3347 actively exploited?

CVE-2021-3347 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 42.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-3347?

CVE-2021-3347 has a CVSS v3 base score of 7.8 (NVD).

How do I remediate CVE-2021-3347?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-3347, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2021-3347

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Is Your Infrastructure Affected by CVE-2021-3347?

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CVE-2021-3347

Published

Last Modified

References (38)

Patch Availability(19)

Weakness Classification(1)

All Vendor Advisories

Data Freshness Timeline

Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-3347?

Same vendor

Same CWE

CVE-2021-3347

📅 Published

🔄 Last Modified

🔗 References (38)

Patch Availability(19)

Weakness Classification(1)

All Vendor Advisories

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-3347?

🔗 Related CVEs(same vendor + same CWE)

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References (38)

Frequently asked(5)

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