Vulnerability · Published Jul 23, 2026 · Assigned by Meta
CVE-2026-44909
High 7.5
In plain English
A high-severity security flaw in proxygen from Facebook. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 48% of all known vulnerabilities).
Official description
Proxygen lacked a generalized slow-consumer detection mechanism in its core HTTP session layer. A remote, unauthenticated attacker could exploit HTTP/2 flow-control by setting SETTINGS_INITIAL_WINDOW_SIZE to 0 or withholding WINDOW_UPDATE frames, causing the server to buffer complete response bodies in memory indefinitely for stalled streams. By opening many simultaneous streams requesting large resources while preventing the server from transmitting responses, an attacker could induce unbounded memory growth leading to service degradation, resource exhaustion, or denial of service. Versions v2017.01.16.00 through v2026.07.20.00 are affected.