Desk Phone 9841 FirmwareOperating system · Cisco
CVE-2025-20336
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 in the directory permissions of Cisco Desk Phone 9800 Series, Cisco IP Phone 7800 and 8800 Series, and Cisco Video Phone 8875 could allow an unauthenticated, remote attacker to access sensitive information on an affected device. This vulnerability exists because the product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. An attacker could exploit this vulnerability by sending a crafted packet to the IP address of a device that has Web Access enabled. A successful exploit could allow the attacker to access sensitive information from the device. Note: To exploit this vulnerability, Web Access must be enabled on the phone. Web Access is disabled by default.
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 confidenceThis is an information disclosure vulnerability in Cisco desk phones (9800 Series, IP Phone 7800/8800 Series, and Video Phone 8875) caused by improper directory permissions that expose sensitive information. An unauthenticated remote attacker can exploit this by sending crafted packets to the IP address of an affected device with Web Access enabled, allowing access to sensitive device data without authentication.
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
Desk Phone 9841 FirmwareOperating system
>= 3.0\(1\), < 3.3\(1\)
Desk Phone 9851 FirmwareOperating system
>= 3.0\(1\), < 3.3\(1\)
Desk Phone 9861 FirmwareOperating system
>= 3.0\(1\), < 3.3\(1\)
Desk Phone 9871 FirmwareOperating system
>= 3.0\(1\), < 3.3\(1\)
Ip Phone 8841 FirmwareOperating system
< 14.3\(1\)= 14.3\(1\)
Ip Phone 7811 FirmwareOperating system
< 14.3\(1\)= 14.3\(1\)
Ip Phone 7821 FirmwareOperating system
< 14.3\(1\)= 14.3\(1\)
Ip Phone 7841 FirmwareOperating system
< 14.3\(1\)= 14.3\(1\)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
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/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 checksWork through these to decide whether this CVE applies to you.
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Identify the phone modelAccess the phone's web interface or check the physical device label to determine the exact model number (e.g., Cisco IP Phone 7841, Cisco Desk Phone 9851)Affected if Model is one of: 9841, 9851, 9861, 9871, 8841, 7811, 7821, or 7841
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Check the firmware versionLog into the phone's web interface and navigate to the About or Status page to view the firmware version, or access it via the phone menu under Settings > Phone InformationAffected if For Desk Phones (9841/9851/9861/9871): version is 3.0(1) or higher but below 3.3(1); for IP Phones (8841/7811/7821/7841): version is 14.3(1) or any version below 14.3(1)
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Verify if Web Access is enabledLog into the phone's web interface and navigate to Security settings or Administration settings to check if the Web Access feature is enabled; alternatively, attempt to access HTTP/HTTPS on the phone's IP address from a remote systemAffected if Web Access is enabled and the device is reachable over the network on HTTP/HTTPS ports
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Confirm network exposureDetermine if the phone's IP address is accessible from untrusted networks by checking network segmentation and firewall rules; scan the phone's IP address on ports 80 and 443 to verify web service availabilityAffected if The phone's web interface is reachable from network segments outside the trusted administration network
The device is affected if it is a listed model, runs a firmware version within the affected ranges, AND has Web Access enabled and network-accessible.
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.
dbcve · scoped3.314.3
Disable Web Access on affected phones if not required for business operations; if Web Access is necessary, apply Cisco firmware updates when available. Verify that default configurations are maintained post-update.
Cisco Desk Phone 9800 Series: upgrade to firmware 3.3(1) or later; Cisco IP Phone 7800/8800 Series: upgrade to firmware version greater than 14.3(1)
- 1. Identify all affected Cisco Desk Phone 9800 Series and IP Phone 7800/8800 Series devices on the network.
- 2. Verify that Web Access is enabled on the affected devices (this is required for exploitation).
- 3. Obtain the latest firmware version from Cisco's official download site for your specific phone model.
- 4. Upgrade the firmware on each affected device to version 3.3(1) or later for Desk Phone 9800 Series (9841, 9851, 9861, 9871).
- 5. For IP Phone 7800/8800 Series (8841, 7811, 7821, 7841), upgrade to a version greater than 14.3(1).
- 6. After upgrade, verify the new firmware version is installed and the vulnerability is resolved.
- 7. As an additional mitigation (if upgrade is not immediately possible), disable Web Access on the phones via the phone's administration web interface or Cisco Unified Communications Manager configuration.
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Desk Phone 9841 Firmware
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,600.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-20336 — 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-2025-20336 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
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