Analyst readout for executives and security teams
Plain-English summary
This Chrome for Mac flaw could let a remote attacker run code inside Chrome’s sandbox if a user opens a crafted HTML page. It is high severity because impact is rated high across confidentiality, integrity, and availability, but the supplied sources do not show active exploitation.
Executive priority
Treat as a high-priority browser patching issue for Mac fleets. The business urgency is driven by remote web delivery and high impact ratings, not by confirmed active exploitation in the supplied evidence.
Technical view
CVE-2026-9999 is an inappropriate implementation issue in ANGLE affecting Google Chrome on Mac before 148.0.7778.216. The CVSS 3.1 score is 8.8, with network attack vector, low complexity, no privileges required, and user interaction required. Chromium rates it High severity.
Likely exposure
Organizations with macOS endpoints running Google Chrome versions earlier than 148.0.7778.216 are the likely exposed population. Exposure depends on patch level and whether users can browse untrusted web content.
Exploitation context
The source says exploitation requires a crafted HTML page and can execute arbitrary code inside a sandbox. KEV is false, and the provided bundle does not cite confirmed in-the-wild exploitation or public exploit availability.
Researcher notes
Evidence is limited to the CVE metadata and Chromium references. The Chromium issue may have restricted details. Do not assume sandbox escape, cross-platform impact, exploit maturity, or additional affected products without vendor confirmation.
Mitigation direction
- Update Chrome on macOS to 148.0.7778.216 or later.
- Enforce browser auto-update across managed Mac fleets.
- Check Google Chrome Releases for any revised vendor guidance.
- Prioritize users with broad internet browsing or sensitive data access.
Validation and detection
- Inventory macOS endpoints running Google Chrome.
- Confirm installed Chrome versions are 148.0.7778.216 or later.
- Review endpoint management telemetry for failed Chrome updates.
- Track vulnerability scanner results for CVE-2026-9999 closure.
Public sources used
Based on public source material and reviewed before publication.
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-269: Authorization and privilege behavior lookup
Authorization weaknesses can support privilege escalation and valid-account review, depending on exploit path. 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 lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-9999 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
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:R/S:U/C:H/I:H/A:H 2.8 5.9 CISA-ADP Vulnerability scoring details
Base CVSS 3.1 score
8.8 HighVector: 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 reserved CVE Program
The CVE ID was reserved by the assigning CNA.
- CVE published CVE Program
The CVE record was published.
- CVE updated CVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 source CVE List V5
- https://chromereleases.googleblog.com/2026/05/stable-channel-update-for-desktop_0877304591.html CVE reference, Chrome
- https://issues.chromium.org/issues/513364480 CVE reference, Chrome
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 Privilege Management
Improper Privilege Management represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.