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CVE Record

CVE-2016-5294: The Mozilla Updater can be made to choose an arbitrary target working directory for output files resulting...

The Mozilla Updater can be made to choose an arbitrary target working directory for output files resulting from the update process. This vulnerability requires local system access. Note: this issue only affects Windows operating systems. This vulnerability affects Thunderbird < 45.5, Firefox ESR < 45.5, and Firefox < 50.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This is a Windows-only Mozilla updater issue in older Firefox, Firefox ESR, and Thunderbird releases. A local user or process could make the updater write update output files into an unintended working directory. The cited sources do not show active exploitation. Business urgency is mainly for legacy Windows endpoints still running affected Mozilla versions.

Executive priority

Treat this as a legacy endpoint hygiene issue unless affected versions are still present. Prioritize remediation where old Mozilla software runs on shared Windows workstations, jump boxes, or systems with sensitive user context.

Technical view

CVE-2016-5294 affects the Mozilla Updater on Windows for Firefox before 50, Firefox ESR before 45.5, and Thunderbird before 45.5. The updater can be made to select an arbitrary target working directory for update-process output files. The public bundle does not provide CVSS, CWE, exploitability details, or a deeper root-cause analysis.

Likely exposure

Exposure is limited to Windows systems with legacy Firefox < 50, Firefox ESR < 45.5, or Thunderbird < 45.5. Modern supported installations should not be affected based on the stated version thresholds.

Exploitation context

The CVE description says local system access is required. KEV is false, and the supplied sources do not state active exploitation. No remote exploitation path is established in the provided evidence.

Researcher notes

The source bundle establishes affected products, fixed version thresholds, Windows-only scope, and local-access requirement. It does not establish CVSS, CWE mapping, active exploitation, proof-of-concept availability, or precise post-impact outcomes, so those should not be inferred.

Mitigation direction

  • Upgrade Firefox to version 50 or later.
  • Upgrade Firefox ESR to version 45.5 or later.
  • Upgrade Thunderbird to version 45.5 or later.
  • Remove unsupported legacy Mozilla installations from Windows endpoints.
  • Review Mozilla and distribution advisories for package-specific guidance.

Validation and detection

  • Inventory Windows endpoints for Firefox, Firefox ESR, and Thunderbird versions.
  • Confirm no Firefox installation is below version 50.
  • Confirm no Firefox ESR or Thunderbird installation is below version 45.5.
  • Check software deployment records for completed Mozilla update rollout.
  • Document exceptions for isolated or unsupported systems.
Prepared
Confidence
high
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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CVE-2016-5294 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
6Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
MozillaThunderbirdunspecifiedListed
MozillaFirefox ESRunspecifiedListed
MozillaFirefoxunspecifiedListed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.