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CVE Record

CVE-2017-7800: A use-after-free vulnerability can occur in WebSockets when the object holding the connection is freed befo...

A use-after-free vulnerability can occur in WebSockets when the object holding the connection is freed before the disconnection operation is finished. This results in an exploitable crash. 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-2017-7800 is a Mozilla WebSockets memory-lifetime flaw. In affected Firefox, Firefox ESR, and Thunderbird versions, the connection object could be freed before disconnect finished, causing an exploitable crash. This matters mainly where legacy Mozilla clients remain installed or supported.

Executive priority

Treat this as a legacy-client cleanup item unless vulnerable versions are still present. If they are, prioritize remediation because browser and mail-client memory flaws can expose users through normal web or message-driven workflows.

Technical view

The issue is a use-after-free in WebSockets connection teardown. The CVE description names Thunderbird before 52.3, Firefox ESR before 52.3, and Firefox before 55 as affected. Public bundle data does not provide CVSS, CWE, exploit mechanics, or a confirmed code-execution outcome.

Likely exposure

Exposure is most likely on unmanaged desktops, legacy Linux distributions, VDI images, old email clients, or embedded browser environments still running affected Mozilla versions. Modern fully patched Firefox, Firefox ESR, and Thunderbird installations should not match the listed vulnerable ranges.

Exploitation context

The bundle says the crash is exploitable, but provides no exploit details and marks KEV as false. There is no source-backed evidence here of active exploitation, weaponized public exploitation, or observed attacks in the wild.

Researcher notes

Available evidence is limited to the CVE description and advisory references. The key validation question is version presence, not exploit reproduction. Avoid assuming RCE or active exploitation without additional vendor or threat-intelligence evidence.

Mitigation direction

  • Upgrade Firefox to version 55 or later where applicable.
  • Upgrade Firefox ESR to version 52.3 or later.
  • Upgrade Thunderbird to version 52.3 or later.
  • Check Mozilla and operating-system vendor advisories for supported package versions.
  • Retire unsupported legacy browser and mail-client builds.

Validation and detection

  • Inventory installed Firefox, Firefox ESR, and Thunderbird versions.
  • Flag Firefox versions earlier than 55.
  • Flag Firefox ESR versions earlier than 52.3.
  • Flag Thunderbird versions earlier than 52.3.
  • Review Debian, Red Hat, and Gentoo package advisory coverage if those platforms are used.
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-2017-7800 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.