Microsoft Edge (Chromium-based): Access of Resource Using Incompatible Type
CVE-2026-66321 is a critical-severity access of resource using incompatible type vulnerability in Microsoft Edge (Chromium-based) from Microsoft, with a CVSS 3.1 base score of 9.6 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists version 151.0.4129.59 as the first without the flaw, so updating Microsoft Edge (Chromium-based) to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 1.07% chance of exploitation within 30 days, higher than 65% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Microsoft Edge (Chromium-based) to 151.0.4129.59 or a later version.
- Update Edge Chromium to 151.0.4129.59 or a later version.
- Read the advisory on msrc.microsoft.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Microsoft | Microsoft Edge (Chromium-based) | 1.0.0.0 up to, but not including, 151.0.4129.59 | 151.0.4129.59 |
| Microsoft | Edge Chromium | before 151.0.4129.59 | 151.0.4129.59 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- RequiredA user must take an action such as opening a file or link.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.4 | High | CNA (microsoft.com) |
| CVSS 3.1 | 9.6 | Critical | NVD |
Official description
Access of resource using incompatible type ('type confusion') in Microsoft Edge (Chromium-based) allows an unauthorized attacker to execute code over a network.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Access of Resource Using Incompatible Type
The product allocates or initializes a resource such as a pointer, object, or variable using one type, but it later accesses that resource using a type that is incompatible with the original type.
More Access of Resource Using Incompatible Type vulnerabilities (CWE-843)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in Microsoft Edge (Chromium-based)
- 7.4 High severity
- 8.1 High severity
- 8.8 High severity
- 8.8 High severity
Microsoft Windows Command Injection Exploited
- 8.1 High severity
- 7.8 High severity
Recent Access of Resource Using Incompatible Type vulnerabilities
- 8.8 High severity
- 7.5 High severity
- 8.8 High severity
- 9.6 Critical severity
- 9.6 Critical severity
- 9.8 Critical severity
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