Netskope Threat Labs

FILE-PDF Adobe Acrobat PDF SMask height out of bounds write attempt

IPS-SWG

1 SID: 59248

First seen
November 2025
Last seen
November 2025

Detects a PDF exploiting CVE-2021-39843, an out-of-bounds write in Adobe Acrobat's transparency mask handling that can allow code execution. The rule matches the crafted mask heights that public exploits use to write beyond allocated image buffers.