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CVE Record

CVE-2017-7787: Same-origin policy protections can be bypassed on pages with embedded iframes during page reloads, allowing...

Same-origin policy protections can be bypassed on pages with embedded iframes during page reloads, allowing the iframes to access content on the top level page, leading to information disclosure. 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

CVE-2017-7787 is a browser same-origin policy bypass. On pages with embedded iframes, a reload condition could let iframe content read information from the top-level page. This creates a confidentiality risk in affected Mozilla products, especially where users access sensitive web applications through old Firefox, Firefox ESR, or Thunderbird versions.

Executive priority

Treat this as a routine but important legacy-client remediation issue. It is not marked as actively exploited in the provided evidence, but same-origin bypasses can expose sensitive web data and should not remain on production endpoints.

Technical view

The vulnerability affects Thunderbird before 52.3, Firefox ESR before 52.3, and Firefox before 55. Mozilla describes an iframe reload issue that bypasses same-origin protections and permits access to top-level page content. The provided sources do not include CVSS, CWE, exploit details, or proof of active exploitation.

Likely exposure

Exposure is most likely on endpoints still running unsupported or unpatched Mozilla Firefox, Firefox ESR, or Thunderbird builds from before the fixed versions. Managed Linux environments may also be exposed if Debian, Red Hat, or Gentoo security updates were not applied.

Exploitation context

The source bundle does not show CISA KEV listing or active exploitation. The risk depends on a user loading attacker-controlled or compromised content in an affected Mozilla product while sensitive top-level page content is present.

Researcher notes

Key evidence is limited to Mozilla and distribution advisories plus the CVE description. No exploit chain, CVSS vector, CWE, or operational workaround is provided in the bundle. Validation should focus on version and package state rather than reproducing the browser 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 where Mozilla packages are distribution-managed.
  • Check Mozilla and operating system vendor advisories for environment-specific patch guidance.

Validation and detection

  • Inventory installed Firefox, Firefox ESR, and Thunderbird versions across endpoints.
  • Confirm no affected product remains below the fixed version thresholds.
  • Verify Linux package advisory updates were applied on managed systems.
  • Review vulnerability scanner results for CVE-2017-7787 after patching.
  • Check browser usage on sensitive applications for legacy Mozilla clients.
Prepared
Confidence
medium
Sources
10

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-2017-7787 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.