CVE-2021-3444

HIGHNVD 7.87.8—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.8 under NVD CVSS v3. EPSS exploit probability: 0.6%, top 54% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
7.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 7.8Exploit: None knownExposed: 0

A fix is available — apply it.

The bpf verifier in the Linux kernel did not properly handle mod32 destination register truncation when the source register was known to be 0. A local attacker with the ability to load bpf programs could use this gain out-of-bounds reads in kernel memory leading to information disclosure (kernel memory), and possibly out-of-bounds writes that could potentially lead to code execution. This issue was addressed in the upstream kernel in commit 9b00f1b78809 ("bpf: Fix truncation handling for mod32 dst reg wrt zero") and in Linux stable kernels 5.11.2, 5.10.19, and 5.4.101.

CVSS v3
7.8
EG Score
7.8(medium)
EG Risk
40(Track)
EG Risk 40/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity78% × 45%
Exploitation1% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
47%
KEV
Not listed

Published

March 23, 2021

Last Modified

November 21, 2024

References (14)

Vendor Advisories for CVE-2021-3444(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(3)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-image-virtual-hwe-20.04-edge (5.8.0.48.53) @ groovy2026-05-26ubuntu
ubuntugkeop (5.4.0-1009) @ focal2026-05-26ubuntu
redhatkernel-0:4.18.0-348.el82021-11-09redhat

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.

Affected Packages

(5 across 5 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
linux—5.10.19-1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
linux—5.10.19-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
linux—5.10.19-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
linux—5.10.19-1—
Debian:9(1)
PackageVulnerable rangeFixed inDependents
linux-4.194.19.132-1~deb9u1 ... 4.19.194-3~deb9u1 (9 versions)4.19.208-1~deb9u1—

Weakness Classification(2)

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

Additional Vendor Advisories

(3)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 8× in last 7d / 29× 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.

Showing the most recent 100 of 142 total refreshes for this CVE.

  1. 2026-08-25 13:46 UTCEPSS rescore
  2. 2026-08-24 14:13 UTCEPSS rescore
  3. 2026-08-23 00:16 UTCEPSS rescore
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  7. 2026-08-20 06:34 UTCOSV refresh
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  21. 2026-08-05 19:14 UTCEPSS rescore
  22. 2026-08-05 01:41 UTCOSV refresh
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  9. 2026-07-23 14:16 UTCEPSS rescore
  10. 2026-07-23 02:01 UTCEG score recompute
  11. 2026-07-22 22:48 UTCEG score recompute
  12. 2026-07-22 14:06 UTCEPSS rescore
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  18. 2026-07-18 23:59 UTCOSV refresh
  19. 2026-07-18 10:02 UTCEPSS rescore
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  21. 2026-07-16 17:00 UTCEPSS rescore
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  30. 2026-07-12 05:44 UTCEPSS rescore
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  44. 2026-07-02 16:57 UTCEPSS rescore
  45. 2026-07-01 15:04 UTCEPSS rescore
  46. 2026-07-01 06:48 UTCOSV refresh
  47. 2026-06-30 23:20 UTCEPSS rescore
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  49. 2026-06-29 14:04 UTCEPSS rescore
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  74. 2026-06-15 17:46 UTCEPSS rescore
  75. 2026-06-14 23:15 UTCEPSS rescore

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2021-3444?
CVE-2021-3444 is a high vulnerability published on March 23, 2021. The bpf verifier in the Linux kernel did not properly handle mod32 destination register truncation when the source register was known to be 0. A local attacker with the ability to load bpf programs could use this gain out-of-bounds reads in kernel memory leading to information disclosure (kernel…
When was CVE-2021-3444 disclosed?
CVE-2021-3444 was first published in the National Vulnerability Database on March 23, 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-2021-3444 actively exploited?
CVE-2021-3444 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 53.5% of all scored CVEs.
What is the CVSS score of CVE-2021-3444?
CVE-2021-3444 has a CVSS v3 base score of 7.8 (NVD).
How do I remediate CVE-2021-3444?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-3444, 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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