CVE-2021-21725
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 ZTE product has an information leak vulnerability. An attacker with higher authority can go beyond their authority to access files in other directories by performing specific operations, resulting in information leak. This affects: ZXHN H196Q V9.1.0C2.
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 confidenceThis is an authorization bypass vulnerability in ZTE ZXHN H196Q V9.1.0C2 where an authenticated attacker with elevated privileges can perform directory traversal operations to access files outside their authorized directory, resulting in sensitive information disclosure.
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= 9.1.0c2CVSS 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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:A/AC:L/PR:L/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 checksWork through these to decide whether this CVE applies to you.
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Identify device firmware versionAccess the web management interface of the ZTE ZXHN H196Q and navigate to the status or system information page to view the installed firmware version, or use the CLI command 'firmware version' or 'show version' if SSH/Telnet access is availableAffected if The firmware version displayed is exactly 9.1.0C2
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Verify administrative access exposureCheck network configuration or firewall rules to determine if the device's web management interface (typically HTTP on port 80 or HTTPS on port 443) is accessible from external networks or untrusted VLANsAffected if The administrative web interface is reachable from networks outside the trusted local network
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Review for suspicious file access patternsExamine the device system logs or web server access logs for unusual requests containing path traversal sequences such as '../' or '..\' pointing to system files outside the web root directoryAffected if Log entries show path traversal requests that the logged-in user should not have been authorized to perform
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Check for unauthorized privilege escalationInspect the list of local user accounts configured on the device through the administration panel, looking for any unexpected accounts or modifications to existing account privilege levelsAffected if Unknown accounts exist or privilege levels have been altered without administrator action
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Verify network segmentation controlsConfirm that the device is placed behind a perimeter firewall and that only trusted management IP addresses are permitted to access the administrative interfaceAffected if No network filtering is in place to restrict administrative access to trusted sources only
The environment is affected if the ZTE ZXHN H196Q is running firmware version 9.1.0C2 AND the administrative interface is accessible from untrusted networks or accounts, enabling a privileged authenticated attacker to exploit the directory traversal flaw.
Generated from the published advisory. Verify against your own configuration.
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 dataApply vendor firmware updates when available. Until then, implement network segmentation and restrict administrative access to trusted IPs to limit exposure to this path traversal vulnerability.
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-21725 — 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-2021-21725 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
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- 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
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