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CVE-2017-6030· NVD / CVE Program· CNA icscert

Schneider Electric Modicon PLCs Predictable Value Range from Previous Values

A predictable value range from previous values issue was discovered in Schneider Electric Modicon PLCs Modicon M221, firmware versions prior to Version 1.5.0.0, Modicon M241, firmware versions prior to Version 4.0.5.11, and Modicon M251, firmware versions prior to Version 4.0.5.11. The affected products generate insufficiently random TCP initial sequence numbers that may allow an attacker to predict the numbers from previous values. This may allow an attacker to spoof or disrupt TCP connections.

MediumCVSS 6.5 · v3.1—No exploit No fix recorded

Noroxi analysis

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Published
Jun 29, 2017
Updated
Jun 16, 2026
EPSS
2.1% · 81th percentile
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Report tools

JSON

Action score

27

Monitor

Low priority for now.

CVSS
26 / 40 · 6.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
1 / 30 · 2.1%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Affected systems

VendorProduct
schneider-electricmodicon m241 firmware
schneider-electricmodicon m241
schneider-electricmodicon m251 firmware
schneider-electricmodicon m251
schneider-electricmodicon m221 firmware
schneider-electricmodicon m221

Affected versions

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

  • schneider-electric modicon m221 firmwareup to 1.1.1.5 inclusive
  • schneider-electric modicon m241 firmwareup to 4.0.3.20 inclusive
  • schneider-electric modicon m251 firmwareup to 4.0.3.20 inclusive

Versions reported by the vendor

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

  • Schneider Electric Modicon M221

    • before 1.5.0.0affected

  • Schneider Electric Modicon M241

    • before 4.0.5.11affected

  • Schneider Electric Modicon M251

    • before 4.0.5.11affected

Same product

schneider-electric: all records

Other highest-scoring records for the same primary product.

  • CVE-2017-6028An Insufficiently Protected Credentials issue was discovered in Schneider Electric Modicon PLCs Modicon M241, all firmware versions, and Mod
    40Plan
  • CVE-2021-22699Improper Input Validation vulnerability exists in Modicon M241/M251 logic controllers firmware prior to V5.1.9.1 that could cause denial of
    30Monitor
  • CVE-2025-13901CWE-404 Improper Resource Shutdown or Release vulnerability exists that could cause partial Denial of Service on Machine Expert protocol whe
    27Monitor
  • CVE-2024-6528CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability exists that could cause a vulnera
    24Monitor

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.

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).

Technical details

Attack conditions

  • Anyone who can reach it over the internet 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
low · data or configuration can be modified
Availability
low · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
Low
Availability impact
Low

Weakness class (CWE)

CWE-343 · Predictable Value Range from Previous Values

CVSS vector

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

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.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

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

References

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

All records