B426 FirmwareOperating system · Bosch

CVE-2021-23846

MEDIUM · 5.9 CVSS v3.1 Published 2021-06-18
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
68/100
Remediation priority · Elevated
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
When using http protocol, the user password is transmitted as a clear text parameter for which it is possible to be obtained by an attacker through a MITM attack. This will be fixed starting from Firmware version 3.11.5, which will be released on the 30th of June, 2021.

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 · moderate confidence

User passwords are transmitted in cleartext as a URL parameter when using HTTP protocol, allowing interception via Man-in-the-Middle (MITM) attacks on the network path.

MitigationUpgrade to firmware version 3.11.5 or later. Until patched, avoid untrusted networks and consider network segmentation to reduce MITM exposure.

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
B426 FirmwareOperating system
Affected:= 03.01.0004= 03.02.002= 03.03.0009= 03.05.0003

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
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:H/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. Confirm Bosch B426 device model
    Access the device web interface or check the physical device label/marketing to verify the model is B426
    Affected if Device is not a Bosch B426 unit
  2. Identify installed firmware version
    Log into the B426 web interface and navigate to the System or Status page to view the firmware version, or check via the device's administrative console
    Affected if Firmware version matches any of these: 03.01.0004, 03.02.002, 03.03.0009, or 03.05.0003
  3. Determine if HTTP protocol is enabled
    Check the device network settings or observe browser connection when accessing the web interface - look for http:// (not https://) in the URL or check the protocol setting in the device network configuration
    Affected if HTTP protocol is enabled and the login page is accessible over http:// rather than https://
  4. Verify network accessibility
    Confirm the device is accessible on the network where a MITM attack could occur - check if the HTTP traffic traverses untrusted or shared network segments
    Affected if Device is reachable over HTTP on a network where an attacker could intercept traffic

You are affected if you have a Bosch B426 device running firmware version 03.01.0004, 03.02.002, 03.03.0009, or 03.05.0003 AND the device is accessed using HTTP protocol instead of HTTPS.

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

Upgrade to firmware version 3.11.5 or later. Until patched, avoid untrusted networks and consider network segmentation to reduce MITM exposure.

Fix this in B426 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing3.0 h
  • Review / QA2.0 h
17.0 hours of engineering $3,050
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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2021-23846 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

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-2021-23846 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