EUVD-2025-210126
GHSA-w68x-xgg3-m822
Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Local vector because exploitation requires a file to be scanned on the local system; PR:N since any user can introduce a file; UI:R because user file interaction triggers scanning; A:H for antivirus process crash; no confidentiality or integrity impact.
Primary rating from Vendor (GEN).
CVSS VectorVendor: GEN
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Lifecycle Timeline
3DescriptionCVE.org
Use of stack memory after free vulnerability in Avast Antivirus when scanning a malformed Windows PE file may allow Denial-of-Service of the antivirus process.
This issue affects Avast Antivirus, AVG Antivirus, Norton Antivirus, Avast One, and Avast Business Antivirus on Windows, macOS, and Linux for virus definition builds before VPS 25022500.
The affected scanning logic is delivered through a shared Gen Digital virus definition update stream. The same stream feeds the consumer antivirus products listed in this advisory and other Gen Digital products that embed the same engine. Mitigation flows through this update channel; installations at or above the listed build are not vulnerable regardless of which product consumes the stream.
AnalysisAI
Stack use-after-free in the Gen Digital shared antivirus scanning engine crashes the antivirus process when it parses a malformed Windows PE file. Five Gen Digital products share a common virus definition update stream - Avast Antivirus, AVG Antivirus, Norton Antivirus, Avast One, and Avast Business Antivirus across Windows, macOS, and Linux - making all simultaneously vulnerable until the shared definition stream reaches build VPS 25022500. No public exploit has been identified at time of analysis; the impact is limited to a Denial-of-Service of the antivirus process with no confidentiality or integrity loss, and the CVSS score of 5.5 reflects the local, user-interaction-dependent nature of the attack.
Technical ContextAI
The root cause is CWE-590 (Free of Memory Not on the Heap), meaning the scanning engine attempts to release memory that was allocated on the stack rather than the heap - a class of memory-safety error distinct from heap use-after-free but equally capable of corrupting program state or triggering a crash. The affected code path resides in the PE (Portable Executable) file parser within the shared Gen Digital scan engine. Windows PE is a complex binary format with numerous optional headers and section structures; crafted malformed PE files can drive parsers into atypical code paths that mismanage stack-allocated buffers. CPE data confirms five discrete products under the gen_digital vendor namespace (cpe:2.3:a:gen_digital:avast_antivirus, avg_antivirus, norton_antivirus, avast_one, avast_business_antivirus) all consuming the same engine through a shared virus definition update stream, meaning a single upstream fix remediates all affected surfaces simultaneously.
RemediationAI
The primary fix is updating the virus definition stream to VPS 25022500 or any subsequent build; installations at or above this build are not vulnerable regardless of the underlying product or platform. Because Gen Digital delivers the fix through the standard automatic virus definition update channel, most installations with automatic updates enabled will have received the remediation without manual intervention. Administrators managing enterprise deployments of Avast Business Antivirus should verify that definition update policies are not delayed or proxied in a way that holds clients below VPS 25022500. If a temporary workaround is required before the update can be applied - for example in an air-gapped environment - disabling on-access scanning of executable files (PE format) would eliminate the attack surface at the cost of reduced real-time malware detection. No additional vendor patch beyond the definition update is indicated. See https://www.gendigital.com/us/en/contact-us/security-advisories/ for the authoritative advisory.
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