h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. Prior to commit 9265bdd, there is an HTTP/2 state amplification issue that combines HPACK decompression amplification with Slowloris-style stream stalling. Amplified decoded header state can be retained by stalled HTTP/2 streams, and depending on the configuration, additional limits are needed to bound decoded header state and prevent attack. This issue has been fixed by commit 9265bdd.

A weakness has been identified in h2oai h2o-3 up to 7402. This vulnerability affects the function exec of the file h2o-core/src/main/java/water/rapids/ast/prims/misc/AstSetProperty.java of the component Rapids setproperty Primitive Handler. Executing a manipulation can lead to improper access controls. The attack may be performed from remote. The exploit has been made available to the public and could be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.

A security flaw has been discovered in h2oai h2o-3 up to 7402. This affects the function importBinaryModel of the file h2o-core/src/main/java/hex/Model.java of the component JAR Handler. Performing a manipulation results in deserialization. The attack is possible to be carried out remotely. The exploit has been released to the public and may be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.

A vulnerability was identified in h2oai h2o-3 up to 7402. Affected by this issue is the function importFiles of the file h2o-core/src/main/java/water/persist/PersistNFS.java of the component ImportFile API. Such manipulation leads to information disclosure. The attack can be executed remotely. The exploit is publicly available and might be used. The vendor was contacted early about this disclosure but did not respond in any way.

A critical remote code execution vulnerability exists in the unauthenticated REST API endpoint /99/ImportSQLTable in H2O-3 version 3.46.0.9 and prior. The vulnerability arises due to insufficient security controls in the parameter blacklist mechanism, which only targets MySQL JDBC driver-specific dangerous parameters. An attacker can bypass these controls by switching the JDBC URL protocol to jdbc:postgresql: and exploiting PostgreSQL JDBC driver-specific parameters such as socketFactory and socketFactoryArg. This allows unauthenticated attackers to execute arbitrary code on the H2O-3 server with the privileges of the H2O-3 process. The issue is resolved in version 3.46.0.10.

Quicly, an IETF QUIC protocol implementation, is susceptible to a denial-of-service attack prior to commit d9d3df6a8530a102b57d840e39b0311ce5c9e14e. A remote attacker can exploit these bugs to trigger an assertion failure that crashes process using Quicly. Commit d9d3df6a8530a102b57d840e39b0311ce5c9e14e fixes the issue.

A vulnerability has been found in h2oai h2o-3 up to 3.46.08. This affects an unknown function of the file /99/ImportSQLTable of the component H2 JDBC Driver. Such manipulation of the argument connection_url leads to deserialization. The attack may be launched remotely. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

A flaw has been found in h2oai h2o-3 up to 3.46.08. The impacted element is an unknown function of the file /99/ImportSQLTable of the component IBMDB2 JDBC Driver. This manipulation of the argument connection_url causes deserialization. The attack may be initiated remotely. The exploit has been published and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

A deserialization vulnerability exists in h2oai/h2o-3 versions <= 3.46.0.8, allowing attackers to read arbitrary system files and execute arbitrary code. The vulnerability arises from improper handling of JDBC connection parameters, which can be exploited by bypassing regular expression checks and using double URL encoding. This issue impacts all users of the affected versions.

In h2oai/h2o-3 version 3.46.0, the `/99/Models/{name}/json` endpoint allows for arbitrary file overwrite on the target server. The vulnerability arises from the `exportModelDetails` function in `ModelsHandler.java`, where the user-controllable `mexport.dir` parameter is used to specify the file path for writing model details. This can lead to overwriting files at arbitrary locations on the host system.

A vulnerability in the typeahead endpoint of h2oai/h2o-3 version 3.46.0 allows for a denial of service. The endpoint performs a `HEAD` request to verify the existence of a specified resource without setting a timeout. An attacker can exploit this by sending multiple requests to an attacker-controlled server that hangs, causing the application to block and become unresponsive to other requests.

A vulnerability in the `/3/ImportFiles` endpoint of h2oai/h2o-3 version 3.46.1 allows an attacker to cause a denial of service. The endpoint takes a single GET parameter, `path`, which can be recursively set to reference itself. This leads the server to repeatedly call its own endpoint, eventually filling up the request queue and leaving the server unable to handle other requests.

In h2oai/h2o-3 version 3.46.0.2, a vulnerability exists where uploading and repeatedly parsing a large GZIP file can cause a denial of service. The server becomes unresponsive due to memory exhaustion and a large number of concurrent slow-running jobs. This issue arises from the improper handling of highly compressed data, leading to significant data amplification.

In h2oai/h2o-3 version 3.46.0, an endpoint exposing a custom EncryptionTool allows an attacker to encrypt any files on the target server with a key of their choosing. The chosen key can also be overwritten, resulting in ransomware-like behavior. This vulnerability makes it possible for an attacker to encrypt arbitrary files with keys of their choice, making it exceedingly difficult for the target to recover the keys needed for decryption.

In h2oai/h2o-3 version 3.46.0, the endpoint for exporting models does not restrict the export location, allowing an attacker to export a model to any file in the server's file structure, thereby overwriting it. This vulnerability can be exploited to overwrite any file on the target server with a trained model file, although the content of the overwrite is not controllable by the attacker.

In h2oai/h2o-3 version 3.46.0.1, the `run_tool` command exposes classes in the `water.tools` package through the `ast` parser. This includes the `XGBoostLibExtractTool` class, which can be exploited to shut down the server and write large files to arbitrary directories, leading to a denial of service.

A vulnerability in the h2oai/h2o-3 REST API versions 3.46.0.4 allows unauthenticated remote attackers to execute arbitrary code via deserialization of untrusted data. The vulnerability exists in the endpoints POST /99/ImportSQLTable and POST /3/SaveToHiveTable, where user-controlled JDBC URLs are passed to DriverManager.getConnection, leading to deserialization if a MySQL or PostgreSQL driver is available in the classpath. This issue is fixed in version 3.47.0.

A vulnerability in the `/3/ParseSetup` endpoint of h2oai/h2o-3 version 3.46.0.1 allows for a denial of service (DoS) attack. The endpoint applies a user-specified regular expression to a user-controllable string. This can be exploited by an attacker to cause inefficient regular expression complexity, leading to the exhaustion of server resources and making the server unresponsive.

A vulnerability in the `/3/Parse` endpoint of h2oai/h2o-3 version 3.46.0.1 allows for a denial of service (DoS) attack. The endpoint uses a user-specified string to construct a regular expression, which is then applied to another user-specified string. By sending multiple simultaneous requests, an attacker can exhaust all available threads, leading to a complete denial of service.

A vulnerability, which was classified as critical, has been found in h2oai h2o-3 3.46.0.4. This issue affects the function getConnectionSafe of the file /dtale/chart-data/1 of the component JDBC Connection Handler. The manipulation of the argument query leads to deserialization. The attack may be initiated remotely. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

H2O.ai H2O through 3.46.0.4 allows attackers to arbitrarily set the JDBC URL, leading to deserialization attacks, file reads, and command execution. Exploitation can occur when an attacker has access to post to the ImportSQLTable URI with a JSON document containing a connection_url property with any typical JDBC Connection URL attack payload such as one that uses queryInterceptors.

In h2oai/h2o-3 version 3.46.0, the `run_tool` command in the `rapids` component allows the `main` function of any class under the `water.tools` namespace to be called. One such class, `MojoConvertTool`, crashes the server when invoked with an invalid argument, causing a denial of service.

In h2oai/h2o-3 version 3.40.0.4, an exposure of sensitive information vulnerability exists due to an arbitrary system path lookup feature. This vulnerability allows any remote user to view full paths in the entire file system where h2o-3 is hosted. Specifically, the issue resides in the Typeahead API call, which when requested with a typeahead lookup of '/', exposes the root filesystem including directories such as /home, /usr, /bin, among others. This vulnerability could allow attackers to explore the entire filesystem, and when combined with a Local File Inclusion (LFI) vulnerability, could make exploitation of the server trivial.

An S3 bucket takeover vulnerability was identified in the h2oai/h2o-3 repository. The issue involves the S3 bucket 'http://s3.amazonaws.com/h2o-training', which was found to be vulnerable to unauthorized takeover.

External Control of File Name or Path in h2oai/h2o-3