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CVE-2020-5657· NVD / CVE Program· CNA jpcert

Improper neutralization of argument delimiters in a command ('Argument Injection') vulnerability in TCP/IP function included in the firmware

Noroxi assessment

Priority: Monitor (action score 26/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 1% (FIRST EPSS); higher than 63.9% of all records.
  • Someone on the same network segment can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to the record, no fixed version is available yet.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Update when a fix is released; follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Improper neutralization of argument delimiters in a command ('Argument Injection') vulnerability in TCP/IP function included in the firmware of MELSEC iQ-R series (RJ71EIP91 EtherNet/IP Network Interface Module First 2 digits of serial number are '02' or before, RJ71PN92 PROFINET IO Controller Module First 2 digits of serial number are '01' or before, RD81DL96 High Speed Data Logger Module First 2 digits of serial number are '08' or before, RD81MES96N MES Interface Module First 2 digits of serial number are '04' or before, and RD81OPC96 OPC UA Server Module First 2 digits of serial number are '04' or before) allows unauthenticated attackers on adjacent network to stop the network functions of the products via a specially crafted packet.

MediumCVSS 6.5 · v3.1—No exploit No fix recorded
Published
Nov 2, 2020
Updated
Jun 16, 2026
EPSS
1.1% · 64th percentile

Report tools

JSON

Action score

26

Monitor

Low priority for now.

CVSS
26 / 40 · 6.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 1.1%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • No fixed version yet

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2020-5657

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
mitsubishielectricmelsec iq-rj71eip91 firmware
mitsubishielectricmelsec iq-rj71eip91
mitsubishielectricmelsec iq-rj71pn92 firmware
mitsubishielectricmelsec iq-rj71pn92
mitsubishielectricmelsec iq-rd81dl96 firmware
mitsubishielectricmelsec iq-rd81dl96
mitsubishielectricmelsec iq-rd81mes96n firmware
mitsubishielectricmelsec iq-rd81mes96n
mitsubishielectricmelsec iq-rd81opc96 firmware
mitsubishielectricmelsec iq-rd81opc96

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • mitsubishielectric melsec iq-rd81dl96 firmwareall versions
  • mitsubishielectric melsec iq-rd81mes96n firmwareall versions
  • mitsubishielectric melsec iq-rd81opc96 firmwareall versions
  • mitsubishielectric melsec iq-rj71eip91 firmwareall versions
  • mitsubishielectric melsec iq-rj71pn92 firmwareall versions

Versions reported by the vendor

Affected version ranges reported by the assigning authority (jpcert). Independent of NVD's CPE analysis and usually ahead of it.

  • Mitsubishi Electric Corporation MELSEC iQ-R series

    • RJ71EIP91 EtherNet/IP Network Interface Module First 2 digits of serial number are '02' or before, RJ71PN92 PROFINET IO Controller Module First 2 digits of serial number are '01' or before, RD81DL96 Haffected

Same product

mitsubishielectric: all records

Other highest-scoring records for the same primary product.

  • CVE-2020-5656Improper access control vulnerability in TCP/IP function included in the firmware of MELSEC iQ-R series (RJ71EIP91 EtherNet/IP Network Inter
    40Plan
  • CVE-2020-5653Buffer overflow vulnerability in TCP/IP function included in the firmware of MELSEC iQ-R series (RJ71EIP91 EtherNet/IP Network Interface Mod
    40Plan
  • CVE-2020-5658Resource Management Errors vulnerability in TCP/IP function included in the firmware of MELSEC iQ-R series (RJ71EIP91 EtherNet/IP Network In
    31Monitor
  • CVE-2020-5655NULL pointer dereferences vulnerability in TCP/IP function included in the firmware of MELSEC iQ-R series (RJ71EIP91 EtherNet/IP Network Int
    31Monitor
  • CVE-2020-5654Session fixation vulnerability in TCP/IP function included in the firmware of MELSEC iQ-R series (RJ71EIP91 EtherNet/IP Network Interface Mo
    31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Someone on the same network segment can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Adjacent
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-88 · Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')

CVSS vector

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records