orca.securityadvisory

Orca Security: Zoom Zero-Click RCE Flaws Allow Any Meeting Attendee to Compromise All Participants

Orca Security details four Zoom vulnerabilities in the cross-platform annotation engine (libannotate.so): CVE-2026-53413, a stack buffer overflow in CAnnoFormatBlock::Deserialize from unchecked 32-bit character counts, and CVE-2026-53415, a use-after-free in auto-shape metadata handling giving a write-what-where primitive, both enabling zero-click RCE against every meeting participant via crafted annotation messages during screen sharing. Also disclosed are CVE-2026-53414 (heap over-read/DoS) and CVE-2026-53416 (path traversal in the Windows VDI client). The write-up notes a working exploit chain built in under 24 hours with fewer than 20 AI-model prompts, platform-specific exploitation details (macOS ARM64 ASLR bypass, Android heap spraying/vtable corruption), and that E2EE meetings bypass Zoom's server-side message filtering.