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Fencer Intel
medium 5.5

CVE-2021-20607 json

Integer Underflow vulnerability in Mitsubishi Electric GX Works2 versions 1.606G and prior, Mitsubishi Electric MELSOFT Navigator versions…

published 4y ago modified 4mo ago also EUVD-2021-8025

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.0%
EPSS 1.0% chance of exploitation in 30 days, percentile 62%
public exploits
0
none known

Summary

Integer Underflow vulnerability in Mitsubishi Electric GX Works2 versions 1.606G and prior, Mitsubishi Electric MELSOFT Navigator versions 2.84N and prior and Mitsubishi Electric EZSocket versions 5.4 and prior allows an attacker to cause a DoS condition in the software by getting a user to open malicious project file specially crafted by an attacker.

Patch / fix

Is CVE-2021-20607 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSA-21-350-05 updated cvss 5.5

Mitsubishi Electric FA Engineering Software (Update B)

  • Mitsubishi Electric EZSocket <= 5.4 Mitsubishi Electric GX Works2 <= 1.606G Mitsubishi Electric MELSOFT Navigator <= 2.84N
    affected: vendor fix, mitigation “GX Works2: Version 1.610L or later” mitsubishielectric.com

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

Exploit prediction

0.99% chance of exploitation in the next 30 days, higher than 62% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:N/A:P

Affected products

  • n/a Mitsubishi Electric GX Works2; Mitsubishi Electric MELSOFT Navigator; Mitsubishi Electric EZSocket

Classification

Weakness
  • CWE-191 Integer Underflow (Wrap or Wraparound)

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.