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Vulnerability record · public intelligence
CVE-2021-42757
MEDIUM

CVE-2021-42757

Published Dec 8, 2021 · Updated Oct 23, 2026

Severity · CVSSMEDIUM · 6.7
Known exploitationNot listed
EPSS / likelihood0.52%
QFinch risk scoreNot available

Original summary

Normalized public record · Updated Oct 23, 2026

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.

Publisher and source text is retained separately from QFinch interpretation.

QFinch assessment

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.

Evidence: public source records

Affected products

Affected scope reported by the available public evidence
Affected package, product or rangeFix status
Consult the referenced vendor advisory for affected versions.Consult source advisory

Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.

Remediation

Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.

  1. Confirm the affected product and reachable code path exist in your environment.
  2. Apply the vendor-supported patch or mitigation from the primary advisory.
  3. Rescan the exact deployed revision and retain verification evidence.
Review primary references

Evidence coverage

CVENVDEPSS
SSVC priority
LOW
Confidence
Not available
Aliases
None reported

Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.

Sources and record history

  1. https://fortiguard.com/advisory/FG-IR-21-173 ↗

Record history

Published Dec 8, 2021 · Last refreshed Oct 23, 2026