CVE-2025-55181: Facebook Proxygen

Medium severity, CVSS 5.3. EPSS: 0.3% chance of exploitation in the next 30 days.

Sending an HTTP request/response body with greater than 2^31 bytes triggers an infinite loop in proxygen::coro::HTTPQuicCoroSession which blocks the backing event loop and unconditionally appends data to a std::vector per-loop iteration. This issue leads to unbounded memory growth and eventually causes the process to run out of memory.

Affected products

• Facebook Proxygen: from 2025.08.25.00, up to and including 2025.12.01.00

Published 2025-12-02. Last modified 2026-06-17.