CVE-2021-25667
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 · uneditedA vulnerability has been identified in RUGGEDCOM RM1224 (All versions >= V4.3 and < V6.4), SCALANCE M-800 (All versions >= V4.3 and < V6.4), SCALANCE S615 (All versions >= V4.3 and < V6.4), SCALANCE SC-600 Family (All versions >= V2.0 and < V2.1.3), SCALANCE XB-200 (All versions < V4.1), SCALANCE XC-200 (All versions < V4.1), SCALANCE XF-200BA (All versions < V4.1), SCALANCE XM400 (All versions < V6.2), SCALANCE XP-200 (All versions < V4.1), SCALANCE XR-300WG (All versions < V4.1), SCALANCE XR500 (All versions < V6.2). Affected devices contain a stack-based buffer overflow vulnerability in the handling of STP BPDU frames that could allow a remote attacker to trigger a denial-of-service condition or potentially remote code execution. Successful exploitation requires the passive listening feature of the device to be active.
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 analysisData overflows a fixed-size buffer allocated on the stack, overwriting adjacent stack memory — including saved return addresses — which is the classic route to redirecting execution into attacker-supplied code. Crafted input is all it takes. Remediation is strict length checks, safe bounded string and memory functions, and modern stack-protection mitigations.
General guidance for the stack-based buffer overflow class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →
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>= 4.3, < 6.4>= 4.3, < 6.4>= 4.3, < 6.4< 4.1< 6.2< 6.2<= 2.0>= 2.1, < 2.1.3<= 2.0>= 2.1, < 2.1.3CVSS 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
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.
dbcve · scoped2.1.34.16.2
Firmware version 6.4 for M-800/S615/RM1224; 6.2 for XM400/XR500; 4.1 for XB-200/XC-200/XF-200BA/XP-200/XR-300WG; 2.1.3 for SC-600 family
- 1. Identify the specific device model from the affected product list (Ruggedcom RM1224, Scalance M-800, Scalance S615, Scalance SC-600 family, Scalance XB-200, Scalance XC-200, Scalance XF-200BA, Scalance XM400, Scalance XP-200, Scalance XR-300WG, or Scalance XR500)
- 2. Determine the current firmware version installed on the device
- 3. Access the device management interface (web-based or CLI) using administrative credentials
- 4. Download the corresponding firmware update from Siemens Industry Support: https://cert-portal.siemens.com/productcert/html/ssa-979775.html
- 5. For Ruggedcom RM1224, Scalance M-800, or Scalance S615: upgrade to firmware version 6.4 or later
- 6. For Scalance XM400 or Scalance XR500: upgrade to firmware version 6.2 or later
- 7. For Scalance X300wg, XB-200, XC-200, XF-200BA, XP-200, or XR-300WG: upgrade to firmware version 4.1 or later
- 8. For Scalance SC622 2c or SC632 2c: upgrade to firmware version 2.1.3 or later
Generated from the published advisory — verify against the referenced sources before acting.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-25667 — 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 sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-25667 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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.
- 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