CVE-2021-20608
No exploitation reported by the sources we read.
- Published2021-12-17
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « affected ».With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.
Description
Improper Handling of Length Parameter Inconsistency vulnerability in Mitsubishi Electric GX Works2 versions 1.606G and prior allows a remote unauthenticated attacker to cause a DoS condition in GX Works2 by getting GX Works2 to read a tampered program file from a Mitsubishi Electric PLC by sending malicious crafted packets to tamper with the program file.
Timeline
dates in UTC- 2021-12-1717:15CVE publishedNVD
Observed activity
isMalicious corpus · updated 2026-10-23 21:37 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-20608?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-20608?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
NVD| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 1.606 | ≤ 1.606g | no fix published | NVD |
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Distribution builds and vendor advisories
Packages from OSV.dev and products from the vendors' CSAF advisories.
version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.
Vendor advisories
Mitsubishi Electric GX Works2
GX Works2: Versions 1.606G and prior
Fix
- Vendor fix CISA ICSA-21-350-04 · 1 productGX Works2, version 1.610L or later
- Mitigation from the vendor CISA ICSA-21-350-04 · 1 productUnzip the downloaded file (zip format).
- Mitigation from the vendor CISA ICSA-21-350-04 · 1 productRun "setup.exe" in the extracted folder to install.
- Mitigation from the vendor CISA ICSA-21-350-04 · 1 productRestrict the connection of all control system devices and systems to the network so they can only be accessed from trusted networks and hosts.
- Mitigation from the vendor CISA ICSA-21-350-04 · 1 productLocate control system networks and remote devices behind firewalls and isolate them from the business network.
- Mitigation from the vendor CISA ICSA-21-350-04 · 1 productUse virtual private network (VPN) when remote access to Mitsubishi Electric PLC is required.
Advisories and patches
- www.mitsubishielectric.comVendor Advisory
Detection
- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Proof-of-concept repositories
- none listed PoC-in-GitHub
Sources
- NVDCVSS 3.17.5read 2026-10-23
- NVDCVSS 2.05read 2026-10-23
- FIRST EPSSEPSS score2.9 %2026-10-22
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Published
- 2021-12-17
- Last Modified
- 2026-06-17
- NVD status
- Modified
Frequently asked questions
What is CVE-2021-20608?
Is CVE-2021-20608 actively exploited?
What is the CVSS score for CVE-2021-20608?
Running Mitsubishi Electric GX Works2? Hear about its next vulnerability
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Related vulnerabilities
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