CVE-2021-42757

MEDIUMNVD 6.76.7—
EchelonGraph scoreMEDIUM confidence

Score 6.7 from GitHub Security Advisory published 2021-12-09. NVD baseline CVSS 6.7; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
6.7
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 6.7Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

A buffer overflow [CWE-121] in the TFTP client library of FortiOS before 6.4.7 and FortiOS 7.0.0 through 7.0.2, may allow an authenticated local attacker to achieve arbitrary code execution via specially crafted command line arguments.

CVSS v3
6.7
EG Score
6.7(medium)
EPSS
38.2%
KEV
Not listed

Published

December 8, 2021

Last Modified

October 16, 2025

References (2)

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 12× in last 7d / 48× 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.

  1. 2026-07-16 17:00 UTCEPSS rescore
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  3. 2026-07-15 16:55 UTCEPSS rescore
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  66. 2026-05-26 06:45 UTCEG score recompute
  67. 2026-05-26 06:45 UTCGHSA enrichment

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2021-42757?
CVE-2021-42757 is a medium vulnerability published on December 8, 2021. A buffer overflow [CWE-121] in the TFTP client library of FortiOS before 6.4.7 and FortiOS 7.0.0 through 7.0.2, may allow an authenticated local attacker to achieve arbitrary code execution via specially crafted command line arguments.
When was CVE-2021-42757 disclosed?
CVE-2021-42757 was first published in the National Vulnerability Database on December 8, 2021, with the most recent update on October 16, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-42757 actively exploited?
CVE-2021-42757 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 38.2% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-42757?
CVE-2021-42757 has a CVSS v3 base score of 6.7 (NVD).
How do I remediate CVE-2021-42757?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-42757, 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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