Openplc V3 FirmwareOperating system · Openplcproject

CVE-2026-35556

HIGH · 7.5 CVSS v3.1 Published 2026-04-09
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
OpenPLC_V3 is vulnerable to a Plaintext Storage of a Password vulnerability that could allow an attacker to retrieve credentials and access sensitive information.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

OpenPLC_V3 stores user passwords in plaintext rather than using cryptographic hashing. An attacker who gains access to the password storage (e.g., through database compromise, file access, or backup exposure) can retrieve valid credentials in readable form and use them to authenticate as compromised users.

MitigationImplement proper password hashing using a modern algorithm like bcrypt, scrypt, or Argon2, with unique per-password salts. Existing plaintext passwords must be migrated to the new hashed format, and the application must be updated to hash new passwords at creation/change time rather than storing them verbatim.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Openplc V3 FirmwareOperating system
Affected:all versions

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify OpenPLC V3 installation
    Locate the OpenPLC V3 installation directory or firmware and confirm the version matches the affected product (Openplcproject Openplc V3 Firmware)
    Affected if OpenPLC V3 is installed and running
  2. Locate user credential storage
    Search for database files, configuration files, or user record files used by OpenPLC V3 for storing user account information. Common locations include the webserver directory, data folder, or SQLite database files.
    Affected if User credential storage files exist in the OpenPLC installation
  3. Inspect password storage format
    Open the identified credential storage file and examine how passwords are stored for user accounts. Look for whether passwords appear as readable text strings or as cryptographic hash outputs.
    Affected if Passwords appear as plaintext readable strings rather than hashed values like $2a$, $scrypt$, or $argon2$
  4. Verify password hashing implementation
    If a source code or configuration is accessible, check the authentication module for the password storage function. Look for whether the code uses hashing libraries (bcrypt, scrypt, Argon2) or stores passwords directly without transformation.
    Affected if Code stores passwords verbatim without applying any hashing algorithm

If OpenPLC V3 is running and passwords in the user storage are stored as plaintext readable strings rather than hashed values, the environment is affected by CVE-2026-35556.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement proper password hashing using a modern algorithm like bcrypt, scrypt, or Argon2, with unique per-password salts. Existing plaintext passwords must be migrated to the new hashed format, and the application must be updated to hash new passwords at creation/change time rather than storing them verbatim.

Fix this in Openplc V3 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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Scan for this in your stack

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dbcve dependency scanner

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-35556 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data