dbcve.org
Dpc3939 FirmwareOperating system · Cisco

CVE-2017-9492

HIGH · 7.5 CVSS v3.1 Published 2017-07-31
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
Remotely reachable 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
The Comcast firmware on Cisco DPC3939 (firmware version dpc3939-P20-18-v303r20421733-160420a-CMCST); Cisco DPC3939 (firmware version dpc3939-P20-18-v303r20421746-170221a-CMCST); Cisco DPC3939B (firmware version dpc3939b-v303r204217-150321a-CMCST); Cisco DPC3941T (firmware version DPC3941_2.5s3_PROD_sey); and Arris TG1682G (eMTA&DOCSIS version 10.0.132.SIP.PC20.CT, software version TG1682_2.2p7s2_PROD_sey) devices does not include the HTTPOnly flag in a Set-Cookie header for administration applications, which makes it easier for remote attackers to obtain potentially sensitive information via script access to cookies.

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

The affected Comcast firmware on Cisco DPC3939, DPC3939B, DPC3941T, and Arris TG1682G devices fails to include the HTTPOnly flag in Set-Cookie headers for administration applications. This allows client-side scripts to access authentication and session cookies via XSS attacks, enabling attackers to steal credentials or hijack administrative sessions.

MitigationApply vendor firmware updates when available. As a compensating control, disable remote web administration interfaces if not required, and monitor for XSS vulnerabilities in upstream web applications that could be chained with this cookie theft issue.

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
Dpc3939 FirmwareOperating system
Affected:= dpc3939-p20-18-v303r20421733-160420a-cmcst= dpc3939-p20-18-v303r20421746-170221a-cmcst
Dpc3939b FirmwareOperating system
Affected:= dpc3939b-v303r204217-150321a-cmcst
Dpc3941t FirmwareOperating system
Affected:= dpc3941_2.5s3_prod_sey
Arris Tg1682g FirmwareOperating system
Affected:= 10.0.132.sip.pc20.ct= tg1682_2.2p7s2_prod_sey

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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify device model
    Access the device admin interface or check device labeling to confirm the model is Cisco DPC3939, DPC3939B, DPC3941T, or Arris TG1682G
    Affected if Device model is not one of these four models - not affected
  2. Check firmware version
    Log into the device admin panel and navigate to Status or Device Info page to view the firmware version, or use the web interface source/footer information
    Affected if Firmware version does not match any of the listed affected versions (dpc3939-p20-18-v303r20421733-160420a-cmcst, dpc3939-p20-18-v303r20421746-170221a-cmcst, dpc3939b-v303r204217-150321a-cmcst, dpc3941_2.5s3_prod_sey, 10.0.132.sip.pc20.ct, tg1682_2.2p7s2_prod_sey)
  3. Verify admin web interface is accessible
    Attempt to access the device web management interface on the default gateway IP (commonly 192.168.0.1 or 192.168.1.1) via HTTPS or HTTP
    Affected if The admin interface is not accessible from the client being tested - the cookie theft attack cannot be executed in this scenario
  4. Examine Set-Cookie headers for HTTPOnly flag
    Log into the admin interface using a browser developer tool or proxy (Burp Suite, OWASP ZAP). In the response to a successful login, locate the Set-Cookie headers and inspect whether the HttpOnly attribute is present on authentication or session cookies
    Affected if Authentication or session cookies are set WITHOUT the HttpOnly attribute in the Set-Cookie header - vulnerable to XSS cookie theft

The device is affected if it is a Cisco DPC3939/3939B/3941T or Arris TG1682G running one of the listed firmware versions, the admin web interface is accessible, and authentication/session cookies lack the HttpOnly flag in Set-Cookie response headers.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply vendor firmware updates when available. As a compensating control, disable remote web administration interfaces if not required, and monitor for XSS vulnerabilities in upstream web applications that could be chained with this cookie theft issue.

Fix this in Dpc3939 Firmware Scoped from the published advisory
  • Consultation2.0 h
  • Testing3.0 h
  • Review / QA2.0 h
7.0 hours of engineering $1,210
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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-2017-9492 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