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CVE Record

CVE-2017-7823: The content security policy (CSP) "sandbox" directive did not create a unique origin for the document, caus...

The content security policy (CSP) "sandbox" directive did not create a unique origin for the document, causing it to behave as if the "allow-same-origin" keyword were always specified. This could allow a Cross-Site Scripting (XSS) attack to be launched from unsafe content. This vulnerability affects Firefox < 56, Firefox ESR < 52.4, and Thunderbird < 52.4.

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 weakened Firefox and Thunderbird’s sandbox handling for unsafe web content. A page that should have been isolated by CSP sandboxing could retain same-origin behavior, enabling cross-site scripting risk. The issue affects older Mozilla versions only: Firefox before 56, Firefox ESR before 52.4, and Thunderbird before 52.4.

Executive priority

Treat as a legacy hygiene issue unless affected versions remain in use. Prioritize remediation on unmanaged desktops, long-lived servers, and environments that process untrusted web or email content.

Technical view

The CSP sandbox directive failed to create a unique origin for sandboxed documents, making behavior equivalent to always setting allow-same-origin. That undermined origin isolation and could let unsafe content execute XSS in contexts relying on CSP sandbox protections.

Likely exposure

Exposure is mainly legacy endpoints or servers packaging old Mozilla clients, including distro-provided Firefox ESR, Thunderbird, or Icedove/Thunderbird builds. Modern fleets are likely unaffected if browser and mail clients are maintained.

Exploitation context

The provided sources do not show CISA KEV listing or active exploitation. The credible risk is malicious or unsafe content reaching an affected browser or mail client where CSP sandboxing was trusted to isolate it.

Researcher notes

Primary facts come from Mozilla and CVE records. Severity scoring, CWE mapping, and exploit telemetry are absent in the supplied bundle, so risk should be refined using local asset prevalence and vendor package status.

Mitigation direction

  • Upgrade Firefox to version 56 or later.
  • Upgrade Firefox ESR to version 52.4 or later.
  • Upgrade Thunderbird to version 52.4 or later.
  • Apply relevant Debian, Red Hat, or Gentoo vendor security updates.
  • Retire unsupported systems running affected Mozilla packages.

Validation and detection

  • Inventory installed Firefox, Firefox ESR, and Thunderbird versions.
  • Check Linux package versions against distro security advisories.
  • Confirm no endpoints run Firefox before 56.
  • Confirm no endpoints run Firefox ESR or Thunderbird before 52.4.
  • Review systems that render untrusted content with Mozilla-based clients.
Prepared
Confidence
medium
Sources
12

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.

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CVE-2017-7823 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
11Source 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
MozillaFirefoxunspecifiedListed
MozillaFirefox ESRunspecifiedListed
MozillaThunderbirdunspecifiedListed
Weakness

CWE details

No CWE listed

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