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CVE Record

CVE-2017-5438: A use-after-free vulnerability during XSLT processing due to the result handler being held by a freed handl...

A use-after-free vulnerability during XSLT processing due to the result handler being held by a freed handler during handling. This results in a potentially exploitable crash. This vulnerability affects Thunderbird < 52.1, Firefox ESR < 45.9, Firefox ESR < 52.1, and Firefox < 53.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This is a memory safety bug in older Mozilla Firefox, Firefox ESR, and Thunderbird releases. During XSLT processing, Mozilla reported a use-after-free condition that could cause a potentially exploitable crash. The main business risk is outdated browser or mail-client software still present on endpoints.

Executive priority

Prioritize remediation if any affected Mozilla client remains in production. For organizations with fully supported browser and mail-client baselines, this is mainly a legacy exposure cleanup item rather than a current emergency based on the supplied evidence.

Technical view

CVE-2017-5438 is a use-after-free during XSLT processing where a result handler could be retained after its handler was freed. The CVE lists affected versions as Thunderbird before 52.1, Firefox ESR before 45.9 and 52.1, and Firefox before 53.

Likely exposure

Exposure is most likely on legacy workstations, jump boxes, kiosks, or packaged application environments still running the listed Mozilla versions. Current supported Firefox, Firefox ESR, and Thunderbird installations should not match the affected version thresholds in the CVE record.

Exploitation context

The provided bundle says the crash is potentially exploitable, but provides no confirmed exploit chain and KEV is false. Do not assume active exploitation from these sources. Treat this as a legacy client-side memory-corruption risk if vulnerable software remains deployed.

Researcher notes

The bundle lacks CVSS, CWE, exploit evidence, and detailed bug contents. Analysis should stay bounded to Mozilla’s affected-version statements and the CVE description. Additional root-cause or exploitability conclusions require advisory or Bugzilla details not present here.

Mitigation direction

  • Upgrade Firefox to version 53 or later, or a currently supported release.
  • Upgrade Firefox ESR beyond the affected 45.9 and 52.1 thresholds.
  • Upgrade Thunderbird to version 52.1 or later, or a currently supported release.
  • Check Mozilla, Red Hat, and Debian advisories for package-specific remediation guidance.
  • Remove unsupported legacy Mozilla builds from managed endpoints.

Validation and detection

  • Inventory installed Firefox, Firefox ESR, and Thunderbird versions across endpoints.
  • Confirm no host runs Firefox before 53.
  • Confirm no host runs Thunderbird before 52.1.
  • Confirm ESR deployments are not below the fixed ESR thresholds.
  • Review package manager history for Red Hat or Debian security advisory updates.
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-2017-5438 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 ESRunspecified, unspecifiedListed
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.