Security readout for executives and security teams
Plain-English summary
CVE-2026-4714 is a Mozilla Audio/Video component flaw caused by incorrect boundary conditions. Mozilla says it is fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9. The published CVSS impact is availability-only, meaning the main business risk is service disruption or application crashes, not confirmed data theft.
Executive priority
Prioritize normal high-severity patching for Mozilla browsers and mail clients, especially on broadly deployed endpoints. The issue is not currently known to be exploited, but the availability impact and remote attack characteristics justify timely remediation.
Technical view
The CVE is classified as CWE-754 and scored CVSS 7.5: network exploitable, low complexity, no privileges, no user interaction, availability impact high. Mozilla’s description is limited to incorrect boundary conditions in the Audio/Video component. No exploit details are provided in the source bundle, and CISA KEV status is false.
Likely exposure
Organizations using Mozilla Firefox, Firefox ESR, or Thunderbird below the fixed releases should treat endpoints as potentially exposed. Exposure is most relevant on workstations, VDI images, and managed email clients where Mozilla applications are installed and not centrally updated.
Exploitation context
No active exploitation is supported by the provided sources, and the CVE is not listed as KEV in the bundle. The CVSS vector indicates remote, unauthenticated availability impact without user interaction, but public sources here do not describe a working exploit or attack chain.
Researcher notes
The public description is sparse. Treat this as a boundary-condition handling flaw in Mozilla’s Audio/Video component with availability-only CVSS impact. Avoid assuming memory corruption, code execution, or data exposure unless Mozilla publishes additional details. Bugzilla and MFSA advisories are the primary references.
Mitigation direction
- Update Firefox to 149 or later where applicable.
- Update Firefox ESR to 140.9 or later.
- Update Thunderbird to 149 or later where applicable.
- Update Thunderbird ESR to 140.9 or later.
- If unable to patch, monitor Mozilla advisories for vendor guidance.
Validation and detection
- Inventory installed Firefox, Firefox ESR, and Thunderbird versions.
- Confirm managed endpoints report the fixed versions or later.
- Check software deployment logs for failed or deferred Mozilla updates.
- Review vulnerability scanner results against CVE-2026-4714.
- Monitor Mozilla advisories for corrected affected-version details.
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.
CWE-754: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2026-4714 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
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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 vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://bugzilla.mozilla.org/show_bug.cgi?id=2018126CVE reference
- https://www.mozilla.org/security/advisories/mfsa2026-20/CVE reference
- https://www.mozilla.org/security/advisories/mfsa2026-22/CVE reference
- https://www.mozilla.org/security/advisories/mfsa2026-23/CVE reference
- https://www.mozilla.org/security/advisories/mfsa2026-24/CVE reference
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.