The HTTP/2 protocol allows a denial of service (server resource consumption) because request cancellation can reset many streams quickly, as exploited in the wild in August through October 2023.

There exists a denial of service through Data corruption in gRPC-C++ - gRPC-C++ servers with transmit zero copy enabled through the channel arg GRPC_ARG_TCP_TX_ZEROCOPY_ENABLED can experience data corruption issues. The data sent by the application may be corrupted before transmission over the network thus leading the receiver to receive an incorrect set of bytes causing RPC requests to fail. We recommend upgrading past commit e9046b2bbebc0cb7f5dc42008f807f6c7e98e791

@grpc/grps-js implements the core functionality of gRPC purely in JavaScript, without a C++ addon. Prior to versions 1.10.9, 1.9.15, and 1.8.22, there are two separate code paths in which memory can be allocated per message in excess of the `grpc.max_receive_message_length` channel option: If an incoming message has a size on the wire greater than the configured limit, the entire message is buffered before it is discarded; and/or if an incoming message has a size within the limit on the wire but decompresses to a size greater than the limit, the entire message is decompressed into memory, and on the server is not discarded. This has been patched in versions 1.10.9, 1.9.15, and 1.8.22.

Lack of error handling in the TCP server in Google's gRPC starting version 1.23 on posix-compatible platforms (ex. Linux) allows an attacker to cause a denial of service by initiating a significant number of connections with the server. Note that gRPC C++ Python, and Ruby are affected, but gRPC Java, and Go are NOT affected. 

gRPC contains a vulnerability that allows hpack table accounting errors could lead to unwanted disconnects between clients and servers in exceptional cases/ Three vectors were found that allow the following DOS attacks: - Unbounded memory buffering in the HPACK parser - Unbounded CPU consumption in the HPACK parser The unbounded CPU consumption is down to a copy that occurred per-input-block in the parser, and because that could be unbounded due to the memory copy bug we end up with an O(n^2) parsing loop, with n selected by the client. The unbounded memory buffering bugs: - The header size limit check was behind the string reading code, so we needed to first buffer up to a 4 gigabyte string before rejecting it as longer than 8 or 16kb. - HPACK varints have an encoding quirk whereby an infinite number of 0’s can be added at the start of an integer. gRPC’s hpack parser needed to read all of them before concluding a parse. - gRPC’s metadata overflow check was performed per frame, so…

gRPC contains a vulnerability whereby a client can cause a termination of connection between a HTTP2 proxy and a gRPC server: a base64 encoding error for `-bin` suffixed headers will result in a disconnection by the gRPC server, but is typically allowed by HTTP2 proxies. We recommend upgrading beyond the commit in  https://github.com/grpc/grpc/pull/32309 https://www.google.com/url

When gRPC HTTP2 stack raised a header size exceeded error, it skipped parsing the rest of the HPACK frame. This caused any HPACK table mutations to also be skipped, resulting in a desynchronization of HPACK tables between sender and receiver. If leveraged, say, between a proxy and a backend, this could lead to requests from the proxy being interpreted as containing headers from different proxy clients - leading to an information leak that can be used for privilege escalation or data exfiltration. We recommend upgrading beyond the commit contained in  https://github.com/grpc/grpc/pull/33005 https://github.com/grpc/grpc/pull/33005

There exists an vulnerability causing an abort() to be called in gRPC.  The following headers cause gRPC's C++ implementation to abort() when called via http2: te: x (x != trailers) :scheme: x (x != http, https) grpclb_client_stats: x (x == anything) On top of sending one of those headers, a later header must be sent that gets the total header size past 8KB. We recommend upgrading past git commit 2485fa94bd8a723e5c977d55a3ce10b301b437f8 or v1.53 and above.

The package grpc before 1.24.4; the package @grpc/grpc-js before 1.1.8 are vulnerable to Prototype Pollution via loadPackageDefinition.

Google gRPC before 2017-04-05 has an out-of-bounds write caused by a heap-based buffer overflow related to core/lib/iomgr/error.c.