CVE-2026-20214
Description
A vulnerability in the FSG file format parser of ClamAV could allow an unauthenticated, remote attacker to cause a DoS condition, or possibly other expanded impacts, resulting from memory corruption on an affected device.
This vulnerability is due to improper boundary checks for content in FSG files during scanning, which may result in an out-of-bounds buffer write. An attacker could exploit this vulnerability by submitting a crafted file that contains portable executable content compressed with FSG to be scanned by ClamAV on an affected device. A successful exploit could allow the attacker to cause the ClamAV scanning process to terminate, resulting in a DoS condition on the affected software.
Summary dbcve.org
ClamAV's FSG (FastStubGenerator) file format parser lacks proper boundary checks when scanning compressed portable executable content, leading to an out-of-bounds buffer write and memory corruption. An attacker can trigger this by submitting a specially crafted FSG-compressed file to be scanned, causing the ClamAV scanning process to crash.
Mitigation
Update ClamAV to the vendor-provided patched version that fixes the FSG parser boundary validation. If using embedded/legacy ClamAV installations, ensure the updated signatures and engine are deployed across all scanning endpoints.