Live Active security incident? Get immediate response
CVE Record

CVE-2026-9959: Race in WebRTC in Google Chrome on Windows prior to 148.0.7778.216 allowed a remote attacker to leak cross-...

Race in WebRTC in Google Chrome on Windows prior to 148.0.7778.216 allowed a remote attacker to leak cross-origin data via a crafted HTML page. (Chromium security severity: High)

LowCVSS 3.1Not KEV-listed Updated
Discuss exposure Back to CVEs
Glexia's Take moderate

Analyst readout for executives and security teams

Plain-English summary

This Chrome for Windows flaw could let a malicious webpage leak limited cross-origin data through a WebRTC race condition. A user must visit a crafted page, and the attack complexity is high. Google addressed affected Chrome versions before 148.0.7778.216. No source in the bundle shows active exploitation.

Executive priority

Treat this as a timely browser patching item, not an emergency breach indicator. The business risk is limited data exposure from user browsing, reduced by high attack complexity and no active exploitation evidence in the supplied sources.

Technical view

CVE-2026-9959 is a CWE-362 race condition in WebRTC affecting Google Chrome on Windows before 148.0.7778.216. The CVSS vector is network-accessible, high complexity, no privileges, user interaction required, unchanged scope, and low confidentiality impact only. Chromium rates the issue High, while the CVSS score is 3.1.

Likely exposure

Exposure is likely on Windows endpoints running Google Chrome earlier than 148.0.7778.216. The bundle does not support claims about other operating systems, Chromium-derived browsers, or server-side products.

Exploitation context

The described attack uses a crafted HTML page and requires user interaction. The issue is not listed in KEV, and the provided sources do not report exploitation in the wild or public exploit availability.

Researcher notes

Evidence is limited to the CVE description, Chromium release reference, and issue tracker URL. Do not infer exploitability beyond a crafted HTML page. Validate exposure by version and platform, and track whether Google later expands affected scope or publishes technical detail.

Mitigation direction

  • Update Google Chrome on Windows to 148.0.7778.216 or later.
  • Verify enterprise Chrome auto-update policies are working across managed Windows endpoints.
  • Prioritize users with access to sensitive browser-based applications and data.
  • Monitor Google Chrome release notes for any amended guidance.

Validation and detection

  • Inventory Windows devices and record installed Chrome versions.
  • Confirm no managed Windows endpoint remains below 148.0.7778.216.
  • Review browser management telemetry for failed or deferred updates.
  • Check vendor sources for any newly published exploit or mitigation details.
Prepared
Confidence
high
Sources
4

Public sources used

Based on public source material and reviewed before publication.

Potential ATT&CK relevance

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 · low confidence lookup

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 lookup
cve · low confidence lookup

CVE-2026-9959 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profile CVE Program record
Severity
Low
CVSS
3.1 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N

Official CVE source material

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.

1 CVSS vectors
3 Timeline events
1 ADP providers
3 Source links

SSVC decision data

CISA-ADP CISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

CVSS vector scores

1 official score

We 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.

Score Version Severity Vector Exploit Impact Source
3.1 CVSS 3.1 Low CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N 1.6 1.4 CISA-ADP

Vulnerability scoring details

Base CVSS 3.1 score

3.1 Low
CVSS 3.1 vector shape for CVE-2026-9959 Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reserved CVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE published CVE Program

    The CVE record was published.

  3. CVE updated CVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADP CISA ADP Vulnrichment
cvssV3_1other:ssvc

Source materials

Affected products

Products and packages named in the record

Vendor Product Version / package Status
Google Chrome 148.0.7778.216 Listed
Weakness

CWE details

CWE-362

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-362 · source CWE mapping

CWE mapping pending import

This CVE carries a CWE mapping that will resolve to a full Glexia CWE intelligence page after the official CWE import is complete.

Open CWE intelligence Same-CWE CVEs