Security readout for executives and security teams
Plain-English summary
Firefox before version 88 had a browser race condition that could confuse users about which tab or site they were interacting with. In certain cases, such as file-selection prompts, this could lead users to disclose information they did not intend to share.
Executive priority
Treat this as a legacy browser hygiene issue, not an emergency, unless Firefox before 88 remains in production. Prioritize remediation where users handle sensitive files or browse untrusted sites.
Technical view
The issue involved a race condition between requestPointerLock() and setTimeout(), creating a UI/origin-confusion risk across tabs. Mozilla states it could be combined with elements such as input type="file" to mislead user interaction. The source bundle identifies Firefox versions earlier than 88 as affected.
Likely exposure
Exposure is limited to users running Firefox before version 88, especially where legacy browsers can access untrusted or attacker-controlled webpages. Current, supported Firefox deployments are likely not exposed based on the affected-version statement.
Exploitation context
No active exploitation is supported by the provided sources, and the CVE is not listed as KEV. Exploitation appears to require user interaction and a page designed to create browser UI or origin confusion.
Researcher notes
The public description is concise and lacks CVSS, CWE, and detailed exploit prerequisites. Analysis should stay focused on UI/origin confusion and unintended disclosure risk. Do not assume broader code execution or sandbox escape impact.
Mitigation direction
- Upgrade Firefox to version 88 or later.
- Confirm managed endpoints are not running Firefox versions before 88.
- Review Mozilla advisory MFSA 2021-16 for vendor guidance.
- Remove or isolate unsupported legacy Firefox installations.
Validation and detection
- Inventory endpoint browser versions and flag Firefox before 88.
- Check software management records for Firefox 88 or later deployment.
- Review proxy or EDR telemetry for legacy Firefox usage.
- Confirm browser update policy covers unmanaged or kiosk systems.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
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
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CVE-2021-24000 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
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.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://www.mozilla.org/security/advisories/mfsa2021-16/CVE reference · x_refsource_MISC
- https://bugzilla.mozilla.org/show_bug.cgi?id=1694698CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.