Avast Antivirus, Avast One, Avast Premium…: Improper Handling of Insufficient Permissions or Privileges
CVE-2026-80301 is a high-severity improper handling of insufficient permissions or privileges vulnerability in Avast Antivirus, Avast One, Avast Premium Security, Avast Ultimate from Gen Digital, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists version 26.7 as the first without the flaw, so updating Avast Antivirus, Avast One, Avast Premium Security, Avast Ultimate to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.11% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Avast Antivirus, Avast One, Avast Premium Security, Avast Ultimate to 26.7 or a later version.
- Update AVG Antivirus Free, AVG Internet Security, AVG Ultimate to 26.7 or a later version.
- Update Norton Antivirus Plus, Norton 360 Standard, Norton 360 Deluxe, Norton 360 Advanced to 26.7 or a later version.
- Read the advisory on gendigital.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Gen Digital | Avast Antivirus, Avast One, Avast Premium Security, Avast Ultimate | before 26.7 | 26.7 |
| Gen Digital | AVG Antivirus Free, AVG Internet Security, AVG Ultimate | before 26.7 | 26.7 |
| Gen Digital | Norton Antivirus Plus, Norton 360 Standard, Norton 360 Deluxe, Norton 360 Advanced | before 26.7 | 26.7 |
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
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- 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:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H. Scored by CISA (ADP).
Official description
Improper isolation in the Avast sandbox on Windows allows a local, low-privileged attacker executing inside the sandbox to access COM interfaces to the Task Scheduler service, escape containment, and execute code with elevated privileges outside the sandbox. The sandbox virtualizes file system and registry access but does not adequately restrict COM interface access to Task Scheduler. A process inside the sandbox can instantiate COM objects bound to Task Scheduler functionality and invoke methods to schedule and execute tasks on the host system. The Task Scheduler COM pathway is not blocked by the sandbox policy, allowing arbitrary code execution in the host security context. This escape vector bypasses the sandbox's intended process and file isolation boundaries and can be chained with other host-level privilege escalation techniques.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Handling of Insufficient Permissions or Privileges
The product does not handle or incorrectly handles when it has insufficient privileges to access resources or functionality as specified by their permissions. This may cause it to follow unexpected code paths that may leave the product in an invalid state.
How developers prevent this class of flaw
- Compartmentalize the system to have safe areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
- Always check to see if you have successfully accessed a resource or system functionality, and use proper error handling if it is unsuccessful. Do this even when you are operating in a highly privileged mode, because errors or environmental conditions might still cause a failure. For example, environments with highly granular permissions/privilege models, such as Windows or Linux capabilities, can cause unexpected failures.
More Improper Handling of Insufficient Permissions or Privileges vulnerabilities (CWE-280)
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 references
Other vulnerabilities in Avast Antivirus, Avast One, Avast Premium Security, Avast Ultimate
- 8.8 High severity
Recent Improper Handling of Insufficient Permissions or Privileges vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 8.8 High severity
- 8.7 High severity
Spotted an error? Tell us.