Security readout for executives and security teams
Plain-English summary
CVE-2026-2802 is a Mozilla browser and email client flaw involving a race condition in JavaScript garbage collection. Mozilla states it was fixed in Firefox 148 and Thunderbird 148. The rated impact is limited confidentiality and integrity loss, with user interaction required and high attack complexity.
Executive priority
Treat as a normal-priority endpoint patching item, not an emergency based on current evidence. Ensure Mozilla browser and email clients are updated in the next regular security cycle, with faster action for high-risk user groups.
Technical view
The issue is CWE-362, a race condition in the JavaScript GC component. CVSS 3.1 is 4.2: network-reachable, high complexity, no privileges, user interaction required, unchanged scope, low confidentiality and integrity impact, and no availability impact.
Likely exposure
Organizations using Firefox or Thunderbird versions not updated to the Mozilla fixed releases may be exposed. Exposure is most relevant on endpoints where users browse the web or process messages using affected Mozilla software.
Exploitation context
The provided sources do not show active exploitation, and the CVE is not listed as KEV. Exploitation requires user interaction and has high complexity, reducing urgency compared with browser zero-days, but browser and mail-client flaws still warrant routine prompt patching.
Researcher notes
Public details are sparse beyond the component, weakness class, CVSS vector, and fixed releases. Bugzilla and Mozilla advisories are the primary references. Do not assume exploitability details beyond the stated race condition and CVSS impacts.
Mitigation direction
- Update Firefox to version 148 or later per Mozilla advisory guidance.
- Update Thunderbird to version 148 or later per Mozilla advisory guidance.
- Prioritize managed desktops, developer workstations, and users exposed to untrusted web or email content.
- Check Mozilla advisories for any platform-specific update instructions.
Validation and detection
- Inventory installed Firefox and Thunderbird versions across managed endpoints.
- Confirm Firefox reports version 148 or later.
- Confirm Thunderbird reports version 148 or later.
- Review patch-management telemetry for failed or deferred Mozilla updates.
- Monitor Mozilla advisory pages for revisions or additional guidance.
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-362: 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-2026-2802 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
- Medium
- CVSS
- 4.2 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N
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:H/PR:N/UI:R/S:U/C:L/I:L/A:N1.62.5Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
4.2MediumVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://bugzilla.mozilla.org/show_bug.cgi?id=2011069CVE reference
- https://www.mozilla.org/security/advisories/mfsa2026-13/CVE reference
- https://www.mozilla.org/security/advisories/mfsa2026-16/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.
Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.