MongooseApplication · Cesanta

CVE-2017-2895

HIGH · 8.2 CVSS v3.1 Published 2017-11-07
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
91/100
Remediation priority · Urgent
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
An exploitable arbitrary memory read vulnerability exists in the MQTT packet parsing functionality of Cesanta Mongoose 6.8. A specially crafted MQTT SUBSCRIBE packet can cause an arbitrary out-of-bounds memory read potentially resulting in information disclosure and denial of service. An attacker needs to send a specially crafted MQTT packet over the network to trigger this vulnerability.

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

A bounds-checking vulnerability exists in Cesanta Mongoose 6.8's MQTT SUBSCRIBE packet parser. Specially crafted packets with manipulated length fields or topic filters can cause the parser to read memory beyond allocated buffers, leading to information disclosure (exposing sensitive heap/stack contents) and potential denial of service via crash.

MitigationUpdate Cesanta Mongoose to a version that includes the fix for this vulnerability. If updates are not immediately possible, implement network-level filtering to validate MQTT packet structure before forwarding to the affected service, or disable MQTT SUBSCRIBE functionality if not required.

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
MongooseApplication
Affected:= 6.8

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
Low
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H

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 Cesanta Mongoose installation
    Locate the binary or library file that implements Cesanta Mongoose in your environment. Check its version information using commands like 'strings', 'file', or version lookup methods specific to your deployment. If source code is available, check the version define or changelog.
    Affected if The installed version is exactly 6.8
  2. Confirm MQTT protocol support is enabled
    Examine the configuration or build settings of your application that uses Cesanta Mongoose. Look for MQTT-related compile-time flags, runtime configuration options, or module settings that enable MQTT functionality.
    Affected if MQTT support is compiled in or enabled at runtime
  3. Verify MQTT SUBSCRIBE handler is active
    Inspect your application's runtime configuration or network bindings to determine if the MQTT SUBSCRIBE packet handler is actively processing requests. Check for listening ports or configured MQTT topics that accept subscription requests.
    Affected if MQTT SUBSCRIBE processing is active and accepting packets
  4. Check for unusual MQTT traffic patterns
    Monitor network traffic or application logs for MQTT packets, particularly SUBSCRIBE packets. Look for any malformed packets, unexpected length values, or packets that may contain manipulated topic filters.
    Affected if MQTT SUBSCRIBE packets are being processed by the affected version

You are affected if Cesanta Mongoose version 6.8 is deployed AND MQTT SUBSCRIBE functionality is enabled and processing packets.

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

Update Cesanta Mongoose to a version that includes the fix for this vulnerability. If updates are not immediately possible, implement network-level filtering to validate MQTT packet structure before forwarding to the affected service, or disable MQTT SUBSCRIBE functionality if not required.

Fix this in Mongoose Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA3.0 h
15.0 hours of engineering $2,560
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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-2017-2895 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
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