An Insufficiently Protected Credentials issue was discovered in Schneider Electric Modicon PLCs Modicon M241, all firmware versions, and Mod
An Insufficiently Protected Credentials issue was discovered in Schneider Electric Modicon PLCs Modicon M241, all firmware versions, and Modicon M251, all firmware versions. Log-in credentials are sent over the network with Base64 encoding leaving them susceptible to sniffing. Sniffed credentials could then be used to log into the web application.
- Published
- Jun 29, 2017
- Updated
- Jun 16, 2026
- EPSS
- 2.3% · 82th percentile
- CWE
- CWE-522
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Report tools
Action score
40
Plan
Add it to your regular patch cycle.
- CVSS
- 39 / 40 · 9.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 1 / 30 · 2.3%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| schneider-electric | modicon m241 firmware | cpe:2.3:o:schneider-electric:modicon_m241_firmware |
| schneider-electric | modicon m241 | cpe:2.3:h:schneider-electric:modicon_m241 |
| schneider-electric | modicon m251 firmware | cpe:2.3:o:schneider-electric:modicon_m251_firmware |
| schneider-electric | modicon m251 | cpe:2.3:h:schneider-electric:modicon_m251 |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- 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.
n/a Schneider Electric Modicon PLCs
- Schneider Electric Modicon PLCsaffected
Same product
schneider-electric: all recordsOther highest-scoring records for the same primary product.
- 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 whe27Monitor
- CVE-2017-6030Schneider Electric Modicon PLCs Predictable Value Range from Previous Values27Monitor
- CVE-2024-6528CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site
Scripting') vulnerability exists that could cause a vulnera24Monitor
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.
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 researchersFinders, 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).
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
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-522 · Insufficiently Protected CredentialsCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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.
Attack patterns (CAPEC)
- Session SidejackingCAPEC-102likelihood: High · High
- Signature Spoofing by Key TheftCAPEC-474likelihood: Medium · High
- Password Recovery ExploitationCAPEC-50likelihood: Medium · High
- KerberoastingCAPEC-509High
- Modify Existing ServiceCAPEC-551
- Remote Services with Stolen CredentialsCAPEC-555Very High
- Use of Known Domain CredentialsCAPEC-560likelihood: High · High
- Windows Admin Shares with Stolen CredentialsCAPEC-561
ATT&CK techniques
- Remote ServicesT1021
- Remote Services:SMB/Windows Admin SharesT1021.002
- Valid AccountsT1078
- Brute Force:Credential StuffingT1110.004
- Email Collection:Remote Email CollectionT1114.002
- External Remote ServicesT1133
- Create or Modify System ProcessT1543
- Use Alternate Authentication Material:Pass The HashT1550.002
- Use Alternate Authentication Material:Pass The TicketT1550.003
- Unsecured Credentials: Private KeysT1552.004
- Steal or Forge Kerberos TicketsT1558
- Steal or Forge Kerberos Tickets:KerberoastingT1558.003
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange 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.