Security readout for executives and security teams
Plain-English summary
On Windows, affected Mozilla apps could download files with very long names without preserving the Mark of the Web. That means Windows might not show its usual warning before a downloaded executable runs, reducing a user-facing safety check.
Executive priority
Treat as a moderate endpoint hardening issue. It weakens a Windows safety prompt that helps prevent risky execution, but the provided sources do not support active exploitation or broad direct compromise.
Technical view
CVE-2017-7765 is a Windows-only Mark of the Web handling flaw affecting Firefox before 54, Firefox ESR before 52.2, and Thunderbird before 52.2. The issue concerns downloaded files with very long names and missing Windows execution-warning metadata.
Likely exposure
Exposure is limited to Windows systems using the affected Mozilla versions. Non-Windows operating systems are explicitly stated as unaffected. Risk is higher where users download and run Internet-sourced executables.
Exploitation context
The source bundle does not show CISA KEV listing or active exploitation evidence. The impact is a security-warning bypass, not direct code execution by itself; abuse would likely depend on a user opening a downloaded executable.
Researcher notes
The key condition is very long downloaded filenames on Windows causing Mark of the Web data not to be saved. Severity metadata is incomplete in the bundle, with no CVSS or CWE provided. Validate by version and OS scope first.
Mitigation direction
- Upgrade Firefox to version 54 or later.
- Upgrade Firefox ESR to version 52.2 or later.
- Upgrade Thunderbird to version 52.2 or later.
- Check Mozilla advisories for environment-specific guidance.
- Retire unsupported affected Mozilla builds from Windows endpoints.
Validation and detection
- Inventory Windows endpoints for affected Firefox, Firefox ESR, and Thunderbird versions.
- Confirm non-Windows assets are not counted as vulnerable for this CVE.
- Review endpoint telemetry for Internet-downloaded executables with unusually long filenames.
- Verify software deployment policies enforce supported Mozilla versions.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
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
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CVE-2017-7765 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
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.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://www.mozilla.org/security/advisories/mfsa2017-15/CVE reference · x_refsource_CONFIRM
- https://bugzilla.mozilla.org/show_bug.cgi?id=1273265CVE reference · x_refsource_CONFIRM
- https://www.mozilla.org/security/advisories/mfsa2017-17/CVE reference · x_refsource_CONFIRM
- https://www.mozilla.org/security/advisories/mfsa2017-16/CVE reference · x_refsource_CONFIRM
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.