Analyst readout for executives and security teams
Plain-English summary
A malicious web page could make vulnerable Chrome on Mac read past intended WebRTC memory boundaries and expose sensitive process memory. The attacker would need a user to open crafted HTML. The issue is confidentiality-focused: sources do not indicate code execution, data modification, or service outage.
Executive priority
Treat this as a prompt browser patching item for Mac fleets, not a crisis absent exploitation evidence. The business concern is potential exposure of sensitive memory from user browsing activity, so managed update coverage should be verified quickly.
Technical view
CVE-2026-9996 is a CWE-125 out-of-bounds read in Chrome’s WebRTC implementation on Mac before 148.0.7778.216. CVSS 3.1 is 6.5: network reachable, low complexity, no privileges, user interaction required, high confidentiality impact, no integrity or availability impact.
Likely exposure
Organizations with macOS endpoints running Google Chrome below 148.0.7778.216 are the relevant exposure population. Risk is higher where users browse untrusted sites, use unmanaged browsers, or lack timely Chrome update enforcement.
Exploitation context
The provided sources describe remote exploitation through a crafted HTML page, requiring user interaction. The bundle does not show CISA KEV listing or cited evidence of active exploitation. Public issue details may be limited, so exploit maturity is not established from these sources.
Researcher notes
The evidence supports a WebRTC out-of-bounds read with confidentiality impact only. Do not assume Windows, Linux, Edge, or other Chromium-based products are affected from this bundle. The affected/fixed version wording should be reconciled against Google’s stable-channel advisory during remediation tracking.
Mitigation direction
- Update Chrome on Mac to 148.0.7778.216 or the vendor-recommended later stable build.
- Enforce Chrome auto-update through endpoint or browser management policy.
- Prioritize macOS users with high-risk browsing or sensitive browser sessions.
- Check Google’s Chrome release guidance for any additional vendor instructions.
Validation and detection
- Inventory macOS endpoints for installed Chrome versions below 148.0.7778.216.
- Confirm update policy status and successful browser restart after patching.
- Review vulnerability scanner results for CVE-2026-9996 coverage.
- Check whether managed browser channels align with the stable release guidance.
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-125: 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-2026-9996 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
- 6.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/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.
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:N/A:N 2.8 3.6 CISA-ADP Vulnerability scoring details
Base CVSS 3.1 score
6.5 MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
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/513268100 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.
Out-of-bounds Read
Out-of-bounds Read represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.