CVE-2021-3402

CRITICALNVD 9.19.1—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.1 under NVD CVSS v3. EPSS exploit probability: 2.2%, top 19% 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
Trending — 3 sources updated this week
9.1
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 2%CVSS: 9.1Exploit: NoneExposed: 0

A fix is available — apply it.

An integer overflow and several buffer overflow reads in libyara/modules/macho/macho.c in YARA v4.0.3 and earlier could allow an attacker to either cause denial of service or information disclosure via a malicious Mach-O file. Affects all versions before libyara 4.0.4

CVSS v3
9.1
EG Score
9.1(medium)
EG Risk
46(Track)
EG Risk 46/100SSVC: 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
Severity91% × 45%
Exploitation2% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
80.8%
KEV
Not listed

Published

May 14, 2021

Last Modified

November 21, 2024

Advisory Details (5)

Auto-updated Jul 22, 2026
🔬 Proof of concept available. Patch available. Sources: redhat.
generic🟡 PoC Available

Advisory X41-2021-001: Multiple Vulnerabilities in YARA | X41 D-Sec - Penetration Tests and Source Code Audits

https://www.x41-dsec.de/lab/advisories/x41-2021-001-yara/
generic🟡 PoC Available

oss-security - X41 D-Sec GmbH Security Advisory X41-2021-001: Multiple Vulnerabilities in YARA

https://www.openwall.com/lists/oss-security/2021/01/29/2
generic

[SECURITY] Fedora 34 Update: yara-4.1.0-1.fc34 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XXM224OLGI6KAOROLDPPGGCZ2OQVQ6HH/
generic

[SECURITY] Fedora 33 Update: python-yara-4.1.0-1.fc33 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FKNXSH5ERG6NELTXCYVJLUPJJJ2TNEBD/
redhat Patch Available

1930175 – (CVE-2021-3402) CVE-2021-3402 libyara: Integer overflow in libyara/modules/macho/macho.c via a malicious Mach-O file

https://bugzilla.redhat.com/show_bug.cgi?id=1930175

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntuyara-doc (3.4.0+dfsg-2ubuntu0.1~esm1) @ xenial2026-05-26ubuntu

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.

All Vendor Advisories

(1)

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 / 49× 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 108 total refreshes for this CVE.

  1. 2026-07-24 14:15 UTCEPSS rescore
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  3. 2026-07-23 02:01 UTCEG score recompute
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Frequently asked(5)

What is CVE-2021-3402?
CVE-2021-3402 is a critical vulnerability published on May 14, 2021. An integer overflow and several buffer overflow reads in libyara/modules/macho/macho.c in YARA v4.0.3 and earlier could allow an attacker to either cause denial of service or information disclosure via a malicious Mach-O file. Affects all versions before libyara 4.0.4
When was CVE-2021-3402 disclosed?
CVE-2021-3402 was first published in the National Vulnerability Database on May 14, 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-2021-3402 actively exploited?
CVE-2021-3402 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 80.8% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-3402?
CVE-2021-3402 has a CVSS v3 base score of 9.1 (NVD).
How do I remediate CVE-2021-3402?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-3402, 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.

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