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CVE Record

CVE-2019-9816: A possible vulnerability exists where type confusion can occur when manipulating JavaScript objects in obje...

A possible vulnerability exists where type confusion can occur when manipulating JavaScript objects in object groups, allowing for the bypassing of security checks within these groups. *Note: this vulnerability has only been demonstrated with UnboxedObjects, which are disabled by default on all supported releases.*. This vulnerability affects Thunderbird < 60.7, Firefox < 67, and Firefox ESR < 60.7.

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 an older Mozilla browser and mail-client vulnerability involving JavaScript object handling. The practical urgency is reduced because Mozilla says the demonstrated condition relied on UnboxedObjects, which were disabled by default on supported releases. Organizations should still eliminate affected Firefox, Firefox ESR, and Thunderbird versions.

Executive priority

Treat this as a legacy software hygiene issue with moderate urgency. It does not have cited active exploitation in the supplied sources, but affected Mozilla products are common enough that old versions should be removed or upgraded promptly.

Technical view

CVE-2019-9816 describes possible type confusion while manipulating JavaScript objects in object groups, allowing security checks inside those groups to be bypassed. The affected products are Thunderbird before 60.7, Firefox before 67, and Firefox ESR before 60.7. The source bundle does not provide CVSS, CWE, or exploit details.

Likely exposure

Exposure is most likely on legacy endpoints running Firefox below 67, Firefox ESR below 60.7, or Thunderbird below 60.7. Current supported deployments are less likely exposed if updated and using default feature settings.

Exploitation context

The source bundle does not show CISA KEV listing or cited active exploitation. Mozilla notes the issue was only demonstrated with UnboxedObjects, which are disabled by default on all supported releases. Evidence is incomplete on real-world exploitability.

Researcher notes

The main technical constraint is Mozilla's note that demonstration depended on UnboxedObjects, disabled by default on supported releases. The bundle lacks CVSS, CWE, patch diff details, and public exploitation evidence, so avoid overstating exploitability.

Mitigation direction

  • Upgrade Firefox to 67 or later where still present.
  • Upgrade Firefox ESR to 60.7 or later where still present.
  • Upgrade Thunderbird to 60.7 or later where still present.
  • Confirm default settings have not enabled UnboxedObjects.
  • Review Mozilla advisories for product-specific guidance.

Validation and detection

  • Inventory installed Firefox, Firefox ESR, and Thunderbird versions.
  • Flag any Firefox versions below 67.
  • Flag any Firefox ESR or Thunderbird versions below 60.7.
  • Check whether legacy browser preferences changed default object behavior.
  • Confirm remediation through endpoint management or software inventory data.
Prepared
Confidence
medium
Sources
6

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

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CVE-2019-9816 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
5Source 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
MozillaFirefoxunspecifiedListed
MozillaFirefox ESRunspecifiedListed
Weakness

CWE details

No CWE listed

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