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CVE Record

CVE-2017-5449: A possibly exploitable crash triggered during layout and manipulation of bidirectional unicode text in conc...

A possibly exploitable crash triggered during layout and manipulation of bidirectional unicode text in concert with CSS animations. This vulnerability affects Thunderbird < 52.1, Firefox ESR < 52.1, and Firefox < 53.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2017-5449 is a Mozilla browser and mail-client crash involving bidirectional Unicode text and CSS animations. Mozilla described it as possibly exploitable. It affects older Firefox, Firefox ESR, and Thunderbird versions, so current business risk is mainly from legacy or unpatched systems.

Executive priority

Treat this as a legacy exposure cleanup item unless affected versions are still present. Prioritize remediation where old Mozilla clients process untrusted web pages or email content.

Technical view

The issue is triggered during layout and manipulation of bidirectional Unicode text when combined with CSS animations. The source bundle identifies affected products as Firefox before 53, Firefox ESR before 52.1, and Thunderbird before 52.1. No CVSS, CWE, or confirmed exploitation evidence is provided.

Likely exposure

Exposure is most likely on unmanaged endpoints, old ESR deployments, kiosk systems, or legacy Thunderbird installations below the fixed versions. Modern supported Mozilla versions should not be exposed based on the provided affected-version data.

Exploitation context

The bundle says the crash is possibly exploitable, but does not document public exploitation, exploit reliability, or weaponization. CISA KEV status is false, so active exploitation should not be assumed from these sources.

Researcher notes

Evidence is limited to a possibly exploitable crash description and affected version bounds. No CVSS vector, CWE mapping, exploit status, or root-cause detail is included in the provided bundle. Avoid overstating impact without reviewing the linked Mozilla bug and advisories.

Mitigation direction

  • Upgrade Firefox to 53 or later where still applicable.
  • Upgrade Firefox ESR to 52.1 or later where still applicable.
  • Upgrade Thunderbird to 52.1 or later where still applicable.
  • Apply vendor Linux distribution updates, including referenced Red Hat advisories if relevant.
  • Check current Mozilla and OS vendor guidance for legacy deployments.

Validation and detection

  • Inventory Firefox, Firefox ESR, and Thunderbird versions across endpoints.
  • Flag any Firefox version below 53 for remediation review.
  • Flag any Firefox ESR or Thunderbird version below 52.1.
  • Confirm Linux packages include the relevant vendor security errata.
  • Review vulnerability scanner findings against actual installed product versions.
Prepared
Confidence
medium
Sources
9

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-2017-5449 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
8Source 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.