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CVE Record

CVE-2017-7784: A use-after-free vulnerability can occur when reading an image observer during frame reconstruction after t...

A use-after-free vulnerability can occur when reading an image observer during frame reconstruction after the observer has been freed. This results in a potentially 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 analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2017-7784 is a memory safety flaw in older Mozilla Firefox, Firefox ESR, and Thunderbird versions. Handling image frame reconstruction could read an object after it was freed, causing a potentially exploitable crash. The business concern is legacy browser or email-client installations, not current patched releases.

Executive priority

Prioritize remediation if legacy Mozilla clients remain in production or regulated environments. For fully patched fleets, this is mainly a hygiene and audit issue. There is no provided evidence of active exploitation, but browser memory-safety flaws deserve closure because user interaction with content may be enough to trigger crashes.

Technical view

The CVE describes a use-after-free in image observer handling during frame reconstruction. Affected versions are Firefox before 55, Firefox ESR before 52.3, and Thunderbird before 52.3. Mozilla and Linux distribution advisories published fixed package guidance, but the provided sources do not include CVSS details or exploit mechanics.

Likely exposure

Exposure is most likely on unmanaged endpoints, legacy virtual desktops, servers with old browser packages, or Linux distributions that missed 2017 Mozilla security updates. Current supported Firefox and Thunderbird builds should not be affected based on the version bounds provided.

Exploitation context

The source bundle says the crash is potentially exploitable, but it does not show active exploitation. The CVE is not listed as CISA KEV in the provided data. Treat exploit status as unconfirmed unless vendor, threat intelligence, or KEV evidence changes.

Researcher notes

Evidence is limited to the CVE description and linked vendor advisories. The affected component is image frame reconstruction, with a freed image observer read. Do not assume remote code execution or public exploit availability from this bundle alone; validate only version exposure and vendor-fixed package status.

Mitigation direction

  • Upgrade Firefox to version 55 or later where applicable.
  • Upgrade Firefox ESR and Thunderbird to 52.3 or later.
  • Apply relevant Debian, Red Hat, or Gentoo security updates for Mozilla packages.
  • Remove unsupported legacy browser and mail-client builds from managed endpoints.
  • Check Mozilla and OS vendor advisories for platform-specific package guidance.

Validation and detection

  • Inventory Firefox, Firefox ESR, and Thunderbird versions across endpoints and servers.
  • Flag Firefox below 55 and ESR or Thunderbird below 52.3.
  • Confirm Debian, Red Hat, and Gentoo package advisories are applied where relevant.
  • Review vulnerability scanner findings for CVE-2017-7784 and verify remediation evidence.
  • Document any remaining legacy exceptions and compensating controls.
Prepared
Confidence
high
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-2017-7784 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
n/an/an/aListed
Weakness

CWE details

No CWE listed

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