Security readout for executives and security teams
Plain-English summary
CVE-2026-5733 is a high-severity Mozilla Firefox and Thunderbird flaw in WebGPU graphics handling. The sources describe incorrect boundary conditions and memory-safety classes that can threaten confidentiality, integrity, and availability. Mozilla says it was fixed in Firefox 149.0.2 and Thunderbird 149.0.2.
Executive priority
Treat this as a prompt endpoint patching item, especially for users who browse the web or process external email. No active exploitation is evidenced in the provided sources, but the impact rating supports expedited remediation.
Technical view
The vulnerability is in Mozilla's Graphics: WebGPU component and maps to CWE-119 and CWE-787. CVSS 3.1 is 8.8: network attack vector, low complexity, no privileges, user interaction required, unchanged scope, and high impact to confidentiality, integrity, and availability.
Likely exposure
Organizations using Firefox or Thunderbird that have not applied the 149.0.2 fixed releases should treat those endpoints as potentially exposed. The provided bundle does not specify the full affected version range or platform-specific impact.
Exploitation context
The source bundle does not show CISA KEV listing or cite active exploitation. Risk remains meaningful because the flaw is remotely reachable, low complexity, requires no privileges, and only requires user interaction per the CVSS vector.
Researcher notes
Evidence is sufficient for severity and component attribution, but incomplete on exact affected ranges and root-cause details. Bugzilla may contain restricted details. Avoid assuming exploitability beyond the CVSS vector and vendor advisories.
Mitigation direction
- Update Firefox to 149.0.2 where applicable.
- Update Thunderbird to 149.0.2 where applicable.
- Review Mozilla advisory guidance for any platform-specific notes.
- Prioritize managed browsers and email clients on high-risk user endpoints.
Validation and detection
- Inventory Firefox and Thunderbird versions across endpoints.
- Confirm deployed versions match the Mozilla fixed release, 149.0.2.
- Check vulnerability scanner findings against CVE-2026-5733.
- Review Mozilla and Red Hat advisories for updated 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-119: 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 lookupCWE-787: 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-2026-5733 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
- 8.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/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.
SSVC decision data
CVSS vector scores
2 official scoresWe 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:R/S:U/C:H/I:H/A:H2.85.9CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H2.85.9redhat-SADPVulnerability scoring details
Base CVSS 3.1 score
8.8HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Base CVSS 3.1 score
8.8HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- ADP timelineredhat-SADP
Made public.
- CVE publishedCVE Program
The CVE record was published.
- ADP timelineredhat-SADP
Reported to Red Hat.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
- 2026-04-07T13:01:18.871Z: Reported to Red Hat.
- 2026-04-07T12:43:13.804Z: Made public.
Source materials
- CVE List V5 sourceCVE List V5
- https://bugzilla.mozilla.org/show_bug.cgi?id=2022554CVE reference, mozilla
- https://www.mozilla.org/security/advisories/mfsa2026-25/CVE reference, mozilla
- https://www.mozilla.org/security/advisories/mfsa2026-28/CVE reference, mozilla
- https://access.redhat.com/security/cve/CVE-2026-5733CVE reference, redhat-SADP · vdb-entry, x_refsource_REDHAT
- RHBZ#2455902CVE reference, redhat-SADP · issue-tracking, x_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-5733.jsonCVE reference, redhat-SADP · x_sadp-csaf-vex
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 Restriction of Operations within the Bounds of a Memory Buffer
Improper Restriction of Operations within the Bounds of a Memory Buffer represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Out-of-bounds Write
Out-of-bounds Write represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.