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Si R 30b FirmwareOperating system · Fujitsu

CVE-2023-38555

HIGH · 8.8 CVSS v3.1 Published 2023-07-26
Fix available
A fix is available. Upgrade to after 02.54 or later.
See remediation →
93/100
Remediation priority · Urgent
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
Authentication bypass vulnerability in Fujitsu network devices Si-R series and SR-M series allows a network-adjacent unauthenticated attacker to obtain, change, and/or reset configuration settings of the affected products. Affected products and versions are as follows: Si-R 30B all versions, Si-R 130B all versions, Si-R 90brin all versions, Si-R570B all versions, Si-R370B all versions, Si-R220D all versions, Si-R G100 V02.54 and earlier, Si-R G200 V02.54 and earlier, Si-R G100B V04.12 and earlier, Si-R G110B V04.12 and earlier, Si-R G200B V04.12 and earlier, Si-R G210 V20.52 and earlier, Si-R G211 V20.52 and earlier, Si-R G120 V20.52 and earlier, Si-R G121 V20.52 and earlier, and SR-M 50AP1 all versions.

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

This is an authentication bypass vulnerability in Fujitsu Si-R series routers and SR-M series network devices. A network-adjacent unauthenticated attacker can exploit this flaw to obtain, modify, or reset configuration settings on affected devices without providing any valid credentials. The attack does not require remote internet access but rather local network adjacency to the targeted device.

MitigationApply vendor-supplied firmware updates (V02.55 or later for G100/G200, V04.13 or later for G100B/G110B/G200B, V20.53 or later for G210/G211/G120/G121) and restrict network access to trusted administrators using network segmentation and access control lists until patches can be applied.

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
Si R 30b FirmwareOperating system
Affected:all versions
Si R 130b FirmwareOperating system
Affected:all versions
Si R 90brin FirmwareOperating system
Affected:all versions
Si R570b FirmwareOperating system
Affected:all versions
Si R370b FirmwareOperating system
Affected:all versions
Si R220d FirmwareOperating system
Affected:all versions
Si R G100 FirmwareOperating system
Affected:<= 02.54
Si R G200 FirmwareOperating system
Affected:<= 02.54

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
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

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 the device model
    Access the router's web interface or check the device label/menu to confirm it is a Fujitsu Si-R series (30b, 130b, 90brin, 570b, 370b, 220d, G100, G200) or SR-M series device
    Affected if Device is any of the listed Fujitsu Si-R models or SR-M series
  2. Check firmware version on Si-R G100/G200
    In the router web interface, navigate to System > Firmware or Status > Version to view the installed firmware version
    Affected if Firmware version is 02.54 or earlier on Si-R G100 or Si-R G200
  3. Check firmware version on other Si-R models
    In the router web interface, navigate to System > Firmware or Status > Version to view the installed firmware version
    Affected if Any firmware version is installed on Si-R 30b, 130b, 90brin, 570b, 370b, or 220d (all versions are affected)
  4. Verify network exposure
    Confirm the device is accessible from a network segment that includes untrusted or non-administrative systems
    Affected if Device is reachable by network-adjacent attackers without proper network segmentation

If the device is a Fujitsu Si-R G100/G200 with firmware <= 02.54, or any other listed Si-R model at any firmware version, and is network-adjacent to untrusted users, the environment is affected by this authentication bypass vulnerability.

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
Upgrade available Upgrade to a release after 02.54
Interim mitigation

Apply vendor-supplied firmware updates (V02.55 or later for G100/G200, V04.13 or later for G100B/G110B/G200B, V20.53 or later for G210/G211/G120/G121) and restrict network access to trusted administrators using network segmentation and access control lists until patches can be applied.

Fix this in Si R 30b Firmware Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing8.0 h
  • Review / QA4.0 h
30.0 hours of engineering $5,280
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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-2023-38555 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