vulnerability
Nginx: Excessive CPU usage in HTTP/2 with small window updates (CVE-2019-9511)
| Severity | CVSS | Published | Added | Modified |
|---|---|---|---|---|
| 8 | (AV:N/AC:L/Au:N/C:N/I:N/A:C) | Aug 14, 2019 | Aug 14, 2019 | Mar 27, 2026 |
Severity
8
CVSS
(AV:N/AC:L/Au:N/C:N/I:N/A:C)
Published
Aug 14, 2019
Added
Aug 14, 2019
Modified
Mar 27, 2026
Description
Some HTTP/2 implementations are vulnerable to window size manipulation and stream prioritization manipulation, potentially leading to a denial of service. The attacker requests a large amount of data from a specified resource over multiple streams. They manipulate window size and stream priority to force the server to queue the data in 1-byte chunks. Depending on how efficiently this data is queued, this can consume excess CPU, memory, or both.
Solutions
nginx-nginx-upgrade-1_16_1nginx-nginx-upgrade-1_17_3
Rapid7 Labs
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