- Reported
-
- Issued
-
- Package
-
pingora-core
(crates.io)
- Type
-
Vulnerability
- Categories
-
- Keywords
-
#http
#http2
#h2
#hpack
- Aliases
-
- References
-
- CVSS Score
- 8.7
HIGH
- CVSS Details
-
- Attack Complexity
- Low
- Attack Requirements
- None
- Attack Vector
- Network
- Privileges Required
- None
- Availability Impact to the Subsequent System
- None
- Confidentiality Impact to the Subsequent System
- None
- Integrity Impact to the Subsequent System
- None
- User Interaction
- None
- Availability Impact to the Vulnerable System
- High
- Confidentiality Impact to the Vulnerable System
- None
- Integrity Impact to the Vulnerable System
- None
- CVSS Vector
- CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- Patched
-
Description
Pingora versions prior to 0.8.1 used the h2 crate's default HTTP/2 server limits, a 16 MiB decoded header-list size and no limit on concurrent streams, unless the application set its own. A remote, unauthenticated client can send 1-byte HPACK references to a near-empty header, making the server allocate hundreds of thousands of header fields per stream across an unlimited number of streams on one connection, and use HTTP/2 flow control to keep those streams open. This can exhaust memory and degrade or terminate the Pingora process.
This affects any Pingora service that terminates HTTP/2 (h2 or h2c) without explicitly setting max_header_list_size and max_concurrent_streams. The reporter showed that a single connection could get a Pingora process with a 2 GiB memory limit OOM-killed.
This flaw was corrected in commit d193c8d49b8b7c1c1ede93183759caa4f6906bbd. When no H2Options are supplied, Pingora now advertises and enforces a 64 KiB decoded header-list limit and at most 100 concurrent streams per connection. Users should upgrade to Pingora >= 0.8.1. Applications that supply their own H2Options are not covered by these defaults and must set max_header_list_size and max_concurrent_streams explicitly, or start from pingora_core::protocols::http::v2::server::default_h2_options(). H2Options::default() does not include these limits.
Note: Cloudflare CDN customers were unaffected, as internal Pingora services at Cloudflare do not have HTTP/2 clients.
Advisory available under CC0-1.0
license.