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CVE Record

CVE-2017-5439: A use-after-free vulnerability during XSLT processing due to poor handling of template parameters.

A use-after-free vulnerability during XSLT processing due to poor handling of template parameters. 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 analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2017-5439 is a Mozilla memory-safety flaw in XSLT processing. A malicious page or content processed by vulnerable Mozilla software could cause a potentially exploitable crash. The affected versions are old Firefox, Firefox ESR, and Thunderbird releases, so business risk mainly comes from legacy desktops, servers, or frozen images still running them.

Executive priority

Prioritize remediation if any legacy Mozilla software remains in production or user-accessible environments. For current managed endpoints, urgency is lower after version validation. The main business concern is preventable exposure from old browsers or mail clients that should already be upgraded or retired.

Technical view

The vulnerability is a use-after-free during XSLT processing caused by poor handling of template parameters. The CVE record says it affects Thunderbird before 52.1, Firefox ESR before 45.9 and before 52.1, and Firefox before 53. Public sources in the bundle do not provide CVSS, CWE, or detailed exploitation prerequisites.

Likely exposure

Exposure is most likely on unmanaged endpoints, legacy Linux packages, VDI images, kiosks, or mail clients still using affected Mozilla versions. Modern supported Firefox, Firefox ESR, and Thunderbird releases should not be assumed exposed based on this bundle.

Exploitation context

The source bundle describes a potentially exploitable crash, but does not cite active exploitation. The KEV flag is false, and no provided source says it is being exploited in the wild. Treat it as a legacy memory-corruption risk, not confirmed active exploitation.

Researcher notes

The bundle gives the root cause and affected product thresholds but lacks CVSS, CWE, exploit maturity, and detailed patch mechanics. Avoid over-claiming impact beyond a potentially exploitable crash. Focus validation on version evidence and distribution package advisories rather than exploit reproduction.

Mitigation direction

  • Upgrade Firefox to 53 or later, or a supported current release.
  • Upgrade Firefox ESR to 45.9, 52.1, or a supported current ESR.
  • Upgrade Thunderbird to 52.1 or a supported current release.
  • Apply Red Hat or Debian vendor security updates where Mozilla packages are distribution-managed.
  • Retire unsupported images that cannot receive fixed browser or mail-client packages.

Validation and detection

  • Inventory Firefox, Firefox ESR, and Thunderbird versions across endpoints and images.
  • Confirm no installed Firefox version is below 53.
  • Confirm no installed Thunderbird version is below 52.1.
  • Check Linux package status against Red Hat and Debian advisories in the bundle.
  • Review vulnerability scanner findings for legacy Mozilla packages and stale golden images.
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-2017-5439 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.