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CVE Record

CVE-2017-7753: An out-of-bounds read occurs when applying style rules to pseudo-elements, such as ::first-line, using cach...

An out-of-bounds read occurs when applying style rules to pseudo-elements, such as ::first-line, using cached style data. 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 analysisunknown

Security readout for executives and security teams

Plain-English summary

This is an older Mozilla client vulnerability involving how Firefox and Thunderbird handled CSS pseudo-element styling. The source bundle identifies affected versions but provides no CVSS score, CWE, or confirmed exploitation. Business urgency is mainly legacy exposure: systems still running pre-2017 Mozilla builds should be upgraded or retired.

Executive priority

Prioritize this as a legacy hygiene issue unless affected versions are found in production. If vulnerable clients remain, remediation should be scheduled promptly because browsers and mail clients process untrusted content routinely.

Technical view

CVE-2017-7753 is an out-of-bounds read during application of cached style data to pseudo-elements such as ::first-line. The bundle says it affects Thunderbird before 52.3, Firefox ESR before 52.3, and Firefox before 55. Impact details beyond out-of-bounds read are not provided.

Likely exposure

Exposure is most likely on unmanaged endpoints, old Linux distributions, kiosk systems, lab images, or email clients still using vulnerable Firefox, Firefox ESR, or Thunderbird versions. Current supported builds should not be affected based on the listed version thresholds.

Exploitation context

The provided sources do not show CISA KEV listing or active exploitation. They also do not provide exploit maturity details. Validation should focus on installed versions and vendor package advisory status, not exploit reproduction.

Researcher notes

The bundle lacks CVSS, CWE, detailed impact, and exploitation evidence. Analysis is therefore limited to the Mozilla description and vendor advisory references. Avoid assuming code execution or active exploitation without additional cited evidence.

Mitigation direction

  • Upgrade Firefox to version 55 or later.
  • Upgrade Firefox ESR to version 52.3 or later.
  • Upgrade Thunderbird to version 52.3 or later.
  • Apply relevant Debian, Red Hat, or Gentoo security updates.
  • Check Mozilla and OS vendor advisories for environment-specific guidance.

Validation and detection

  • Inventory installed Firefox, Firefox ESR, and Thunderbird versions.
  • Identify systems running versions below the fixed thresholds.
  • Check Linux package versions against Debian, Red Hat, or Gentoo advisories.
  • Confirm vulnerable legacy packages are upgraded or removed.
  • Record unsupported endpoints requiring compensating controls or retirement.
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-2017-7753 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.