Security readout for executives and security teams
Plain-English summary
CVE-2026-2801 is a high-severity Mozilla issue in the JavaScript WebAssembly component. The reported impact is availability only: a remote, unauthenticated attacker could potentially cause a denial of service. Mozilla states it was fixed in Firefox 148 and Thunderbird 148. No provided source indicates active exploitation.
Executive priority
Treat this as a prompt patching item, not an emergency based on current evidence. The main business risk is disruption from application crashes or denial of service. Prioritize broad desktop fleets and users dependent on Firefox or Thunderbird.
Technical view
The flaw is described as incorrect boundary conditions in JavaScript: WebAssembly, mapped to CWE-754. CVSS 3.1 is 7.5: network attack vector, low complexity, no privileges or user interaction, unchanged scope, and high availability impact only. Public details are limited in the provided sources.
Likely exposure
Organizations running Mozilla Firefox or Thunderbird before applying the vendor-fixed 148 releases may be exposed. Internet-facing browsing and email usage increases practical exposure, but the provided sources do not identify specific platforms or configurations.
Exploitation context
The CVSS vector suggests remote unauthenticated denial-of-service potential without user interaction. However, the source bundle does not provide exploit details, proof of concept, or evidence of exploitation in the wild. It is not listed as KEV in the provided data.
Researcher notes
Public information is sparse. The Bugzilla reference may contain limited or restricted details. Analysis should stay anchored to Mozilla advisories, the CVE record, and version validation. Do not assume memory corruption, code execution, or active exploitation from the provided data.
Mitigation direction
- Review Mozilla advisories MFSA 2026-13 and MFSA 2026-16.
- Update Firefox to version 148 or a later vendor-supported release.
- Update Thunderbird to version 148 or a later vendor-supported release.
- Prioritize managed endpoints where browsers or email clients are widely deployed.
- If updates are delayed, follow Mozilla guidance for any available workarounds.
Validation and detection
- Inventory installed Firefox and Thunderbird versions across endpoints.
- Confirm Firefox installations are version 148 or later.
- Confirm Thunderbird installations are version 148 or later.
- Check vulnerability management tools for CVE-2026-2801 detection coverage.
- Review endpoint crash or availability telemetry for unusual browser or Thunderbird instability.
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-2026-2801 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=2009901CVE 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.
Improper Check for Unusual or Exceptional Conditions
Improper Check for Unusual or Exceptional Conditions represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.