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CVE Record

CVE-2017-7791: On pages containing an iframe, the "data:" protocol can be used to create a modal alert that will render ov...

On pages containing an iframe, the "data:" protocol can be used to create a modal alert that will render over arbitrary domains following page navigation, spoofing of the origin of the modal alert from the iframe content. This vulnerability affects Thunderbird < 52.3, Firefox ESR < 52.3, and Firefox < 55.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This flaw could let a malicious page make a browser alert appear to come from a different site. The main business risk is deception: users may trust a misleading message shown over a legitimate domain. The source bundle does not show active exploitation.

Executive priority

Treat as a hygiene and phishing-resilience issue. Prioritize remediation where legacy Mozilla clients remain in production, especially on managed endpoints or systems used for sensitive webmail, administration, or customer workflows.

Technical view

CVE-2017-7791 is an origin-spoofing issue involving pages with iframes and the data: protocol. A modal alert could render over arbitrary domains after navigation, making the alert appear associated with iframe content. It affects Thunderbird before 52.3, Firefox ESR before 52.3, and Firefox before 55.

Likely exposure

Exposure is likely limited to endpoints running obsolete Mozilla Firefox, Firefox ESR, or Thunderbird versions, or older enterprise Linux packages that shipped affected builds. Modern, supported deployments should be unaffected if vendor security updates were applied.

Exploitation context

The bundle describes a user-deception condition, not code execution or privilege escalation. KEV is false, and no provided source states active exploitation. Practical abuse would depend on persuading users to interact with deceptive browser or mail-client content.

Researcher notes

Evidence is sufficient for affected-version boundaries and vulnerability class, but the bundle lacks CVSS, CWE, detailed exploitability analysis, and active exploitation evidence. Avoid assuming broader impact beyond spoofed modal-origin trust behavior.

Mitigation direction

  • Upgrade Firefox to version 55 or later.
  • Upgrade Firefox ESR to version 52.3 or later.
  • Upgrade Thunderbird to version 52.3 or later.
  • Apply relevant Debian, Red Hat, or Gentoo security updates.
  • Review Mozilla and OS vendor advisories for environment-specific guidance.

Validation and detection

  • Inventory installed Firefox, Firefox ESR, and Thunderbird versions.
  • Check Linux package versions against Debian, Red Hat, or Gentoo advisories.
  • Confirm unsupported browser and mail-client builds are removed.
  • Review endpoint management data for legacy Mozilla installations.
  • Document exceptions where affected versions cannot be upgraded.
Prepared
Confidence
medium
Sources
11

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-2017-7791 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
10Source 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.