Catalyst Pon Switch Cgp Ont 1p FirmwareOperating system · Cisco
CVE-2021-40112
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 · uneditedMultiple vulnerabilities in the web-based management interface of the Cisco Catalyst Passive Optical Network (PON) Series Switches Optical Network Terminal (ONT) could allow an unauthenticated, remote attacker to perform the following actions: Log in with a default credential if the Telnet protocol is enabled Perform command injection Modify the configuration For more information about these vulnerabilities, see the Details section of this advisory.
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 analysisThe application fails to correctly restrict what a user can do or reach, so functions or resources are available to people who should not have them. Attackers simply probe for the paths where the check is missing or wrong. The fix is to enforce access-control decisions consistently on every request, evaluated against the acting user rather than assumed from context.
General guidance for the improper access control 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
Catalyst Pon Switch Cgp Ont 1p FirmwareOperating system
< 1.1.1.14
Catalyst Pon Switch Cgp Ont 4p FirmwareOperating system
< 1.1.3.17
Catalyst Pon Switch Cgp Ont 4pvc FirmwareOperating system
< 1.1.3.17
Catalyst Pon Switch Cgp Ont 4tvcw FirmwareOperating system
< 1.1.3.17
Catalyst Pon Switch Cgp Ont 4pv FirmwareOperating system
< 1.1.3.17CVSS 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
- None
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
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 · scoped1.1.1.141.1.3.17
Firmware 1.1.1.14 for 1-port models; Firmware 1.1.3.17 for 4-port models
- 1. Identify the exact Cisco Catalyst PON ONT model (1p, 4p, 4pvc, 4tvcw, or 4pv) from the device label or management interface
- 2. Access the device web-based management interface or console
- 3. Navigate to the firmware/software upgrade section (typically under Administration > System Settings or similar)
- 4. Obtain the firmware from Cisco's official software download page for the specific ONT model
- 5. Upload and apply firmware version 1.1.1.14 (for 1p models) or 1.1.3.17 (for 4p/4pvc/4tvcw/4pv models)
- 6. Verify the firmware upgrade completed successfully by checking the firmware version in the device status
- 7. After upgrade, change any default credentials and disable Telnet if not required to reduce attack surface
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-2021-40112 — 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-2021-40112 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