CVE-2021-21295 — Possible request smuggling in HTTP/2 due missing validation

Affected: netty io.netty:netty-codec-http2

Netty is an open-source, asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers & clients. In Netty (io.netty:netty-codec-http2) before version 4.1.60.Final there is a vulnerability that enables request smuggling. If a Content-Length header is present in the original HTTP/2 request, the field is not validated by `Http2MultiplexHandler` as it is propagated up. This is fine as long as the request is not proxied through as HTTP/1.1. If the request comes in as an HTTP/2 stream, gets converted into the HTTP/1.1 domain objects (`HttpRequest`, `HttpContent`, etc.) via `Http2StreamFrameToHttpObjectCodec `and then sent up to the child channel's pipeline and proxied through a remote peer as HTTP/1.1 this may result in request smuggling. In a proxy case, users may assume the content-length is validated somehow, which is not the case. If the request is forwarded to a backend channel that is a HTTP/1.1 connection, the Content-Length now has meaning and needs to be checked. An attacker can smuggle requests inside the body as it gets downgraded from HTTP/2 to HTTP/1.1. For an example attack refer to the linked GitHub Advisory. Users are only affected if all of this is true: `HTTP2MultiplexCodec` or `Http2FrameCodec` is used, `Http2StreamFrameToHttpObjectCodec` is used to convert to HTTP/1.1 objects, and these HTTP/1.1 objects are forwarded to another remote peer. This has been patched in 4.1.60.Final As a workaround,…

USN-6049-1 — netty vulnerabilities

Affected: Ubuntu:Pro:16.04:LTS: netty, Ubuntu:Pro:18.04:LTS: netty, Ubuntu:Pro:20.04:LTS: netty, Ubuntu:22.04:LTS: netty

It was discovered that Netty's Zlib decoders did not limit memory allocations. A remote attacker could possibly use this issue to cause Netty to exhaust memory via malicious input, leading to a denial of service. This issue only affected Ubuntu 16.04 ESM and Ubuntu 20.04 ESM. (CVE-2020-11612)

It was discovered that Netty created temporary files with excessive permissions. A local attacker could possibly use this issue to expose sensitive information. This issue only affected Ubuntu 16.04 ESM, Ubuntu 18.04 ESM, and Ubuntu 20.04 ESM. (CVE-2021-21290)

It was discovered that Netty did not properly validate content-length headers. A remote attacker could possibly use this issue to smuggle requests. This issue was only fixed in Ubuntu 20.04 ESM. (CVE-2021-21295, CVE-2021-21409)

It was discovered that Netty's Bzip2 decompression decoder did not limit the decompressed output data size. A remote attacker could possibly use this issue to cause Netty to exhaust memory via malicious input, leading to a denial of service. This issue only affected Ubuntu 18.04 ESM, Ubuntu 20.04 ESM, Ubuntu 22.04 LTS, and Ubuntu 22.10. (CVE-2021-37136)

It was discovered that Netty's Snappy frame decoder function did not limit chunk lengths. A remote attacker could possibly use this issue to cause Netty to exhaust memory via malicious input, leading to a denial of service. (CVE-2021-37137)

It was discovered that Netty did not properly handle control chars at the beginning and end of header names. A rem…

Most recent entries from all

CVE-2021-21295 — Possible request smuggling in HTTP/2 due missing validation

USN-6049-1 — netty vulnerabilities