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CVE Record

CVE-2017-7801: A use-after-free vulnerability can occur while re-computing layout for a "marquee" element during window re...

A use-after-free vulnerability can occur while re-computing layout for a "marquee" element during window resizing where the updated style object is freed while still in use. 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 analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2017-7801 is a Mozilla memory-safety flaw in old Firefox, Firefox ESR, and Thunderbird versions. A crafted page or rendered HTML involving a marquee element and window resizing could crash the application in a potentially exploitable way. Modern, supported versions should not be affected if patched past the named fixed releases.

Executive priority

Treat this as a legacy-software cleanup item unless affected versions remain in production. If old Mozilla clients are still used for web or email, prioritize remediation because memory-safety browser bugs can create user-driven compromise risk.

Technical view

The issue is a use-after-free during layout recomputation for a marquee element while resizing a window. The style object can be freed while still referenced, causing a potentially exploitable crash. Affected products are Thunderbird before 52.3, Firefox ESR before 52.3, and Firefox before 55.

Likely exposure

Exposure is mainly legacy Mozilla deployments: Firefox below 55, Firefox ESR below 52.3, or Thunderbird below 52.3. Risk is higher where users browse untrusted sites or render untrusted HTML email in those versions.

Exploitation context

The bundle does not show CISA KEV listing or cited evidence of active exploitation. Public text describes a potentially exploitable crash, but does not provide exploit-in-the-wild confirmation or a CVSS score.

Researcher notes

Focus validation on product/version evidence and package backport status. The available bundle supports affected-version boundaries and the use-after-free condition, but not active exploitation, exploit maturity, CVSS, or a specific vendor workaround beyond upgrading or applying distro fixes.

Mitigation direction

  • Upgrade Firefox to 55 or later where applicable.
  • Upgrade Firefox ESR and Thunderbird to 52.3 or later.
  • Apply distribution advisories from Debian, Red Hat, or Gentoo if using packaged Mozilla builds.
  • Retire unsupported legacy Mozilla versions from managed endpoints.
  • Check current vendor guidance for any platform-specific backports.

Validation and detection

  • Inventory Firefox, Firefox ESR, and Thunderbird versions across endpoints.
  • Confirm no installed version is below the fixed release named for that product.
  • Check Linux package versions against Debian, Red Hat, or Gentoo advisories.
  • Review browser and mail-client management reports for unmanaged legacy installs.
  • Document exceptions for isolated systems and compensating controls.
Prepared
Confidence
high
Sources
10

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-2017-7801 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.