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CVE Record

CVE-2017-5451: A mechanism to spoof the addressbar through the user interaction on the addressbar and the "onblur" event.

A mechanism to spoof the addressbar through the user interaction on the addressbar and the "onblur" event. The event could be used by script to affect text display to make the loaded site appear to be different from the one actually loaded within the addressbar. This vulnerability affects Thunderbird < 52.1, Firefox ESR < 52.1, and Firefox < 53.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2017-5451 lets a malicious page make the browser address bar display misleading text after user interaction. The business risk is phishing: users could believe they are on a trusted site when they are not. The supplied sources do not show code execution, data theft by itself, or confirmed active exploitation.

Executive priority

Treat this as a legacy-client cleanup and phishing-risk reduction item, not an emergency based on the supplied evidence. Prioritize remediation where affected browsers are used for email, authentication, admin consoles, or other high-trust workflows.

Technical view

The flaw involves address bar spoofing through user interaction with the address bar and script handling of the onblur event. It affects Mozilla Thunderbird before 52.1, Firefox ESR before 52.1, and Firefox before 53. Mozilla and Red Hat advisories are listed, but the bundle provides no CVSS score or CWE classification.

Likely exposure

Exposure is mainly legacy Mozilla client software: Firefox before 53, Firefox ESR before 52.1, and Thunderbird before 52.1. Organizations with unmanaged browsers, old desktop images, or long-lived ESR deployments are the most plausible exposure points.

Exploitation context

The supplied evidence describes a user-interface deception issue requiring user interaction. It could support phishing or credential-harvesting scenarios by making the loaded site appear different in the address bar. CISA KEV is false, and no supplied source confirms active exploitation.

Researcher notes

The source bundle is thin: no CVSS, no CWE, and no exploit-status evidence beyond KEV false. The key technical point is address bar text manipulation tied to onblur after user interaction. Validate only the named Mozilla product/version boundaries unless vendor advisories add environment-specific package details.

Mitigation direction

  • Upgrade Firefox to version 53 or later where still present.
  • Upgrade Firefox ESR and Thunderbird to 52.1 or later.
  • Apply relevant Red Hat security updates for Mozilla packages.
  • Retire or isolate unsupported legacy Mozilla clients.
  • Check Mozilla and distribution advisories for environment-specific guidance.

Validation and detection

  • Inventory installed Firefox, Firefox ESR, and Thunderbird versions.
  • Flag Firefox versions below 53 as vulnerable.
  • Flag Firefox ESR and Thunderbird versions below 52.1 as vulnerable.
  • Confirm Red Hat Mozilla packages include RHSA-2017:1106 or RHSA-2017:1201 fixes.
  • Review phishing controls for users still running affected clients.
Prepared
Confidence
medium
Sources
8

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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ATT&CK lookup starting points

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CVE-2017-5451 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
7Source 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.