GHSA-qmcv-hh7c-3m56 CVE-2026-3960 PYSEC-2026-2180
H2O-3 is Vulnerable to Code Injection
- Severity
- 5.9 / 10
- Critical · CVSS 3.0
- Exploit chance (EPSS)
- 0.94%
- Chance of exploitation in the next 30 days. Higher than 60.89% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-94 Improper Control of Generation of Code ('Code Injection')
- Fix
- Available
- 2 packages have a fixed version
Description
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.
Affected versions
Maven
| Package | Vulnerable | Fixed in |
|---|---|---|
| ai.h2o:h2o-core | < 3.46.0.10 |
3.46.0.10 |
PyPI
| Package | Vulnerable | Fixed in |
|---|---|---|
| h2o | < 3.46.0.10 |
3.46.0.10 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
ai.h2o:h2o-core Maven → 3.46.0.10
- maven
<dependency><groupId>ai.h2o</groupId><artifactId>h2o-core</artifactId><version>3.46.0.10</version></dependency>- gradle
implementation("ai.h2o:h2o-core:3.46.0.10")
h2o PyPI → 3.46.0.10
- pip
pip install --upgrade "h2o>=3.46.0.10"- poetry
poetry add "h2o>=3.46.0.10"- uv
uv add "h2o>=3.46.0.10"
Severity breakdown
CVSS 3.0 5.9
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Weakness
CWE-94: Improper Control of Generation of Code ('Code Injection')
The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.
How to prevent it
- Architecture and Design: Refactor your program so that you do not have to dynamically generate code.
- Architecture and Design: Run your code in a "jail" or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which code can be executed by your product. Examples include the Unix chroot jail and AppArmor. In general, managed code may provide some protection. This may not be a feasible solution, and it only limits the impact to the operating system; the rest of your application may still be subject to compromise. Be careful to avoid CWE-243 and other weaknesses related to jails.
- Implementation: Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright. To reduce the likelihood of code injection, use stringent allowlists that limit which constructs are allowed. If you are dynamically constructing code that invokes a function, then verifying that the input is alphanumeric might be insufficient. An attacker might still be able to reference a dangerous function that you did not intend to allow, such as system(), exec(), or exit().
- Testing: Use dynamic tools and techniques that interact with the product using large test suites with many diverse inputs, such as fuzz testing (fuzzing), robustness testing, and fault injection. The product's operation may slow down, but it should not become unstable, crash, or generate incorrect results.
- Operation: Run the code in an environment that performs automatic taint propagation and prevents any command execution that uses tainted variables, such as Perl's "-T" switch. This will force the program to perform validation steps that remove the taint, although you must be careful to correctly validate your inputs so that you do not accidentally mark dangerous inputs as untainted (see CWE-183 and CWE-184).
- Operation: Run the code in an environment that performs automatic taint propagation and prevents any command execution that uses tainted variables, such as Perl's "-T" switch. This will force the program to perform validation steps that remove the taint, although you must be careful to correctly validate your inputs so that you do not accidentally mark dangerous inputs as untainted (see CWE-183 and CWE-184).
- Implementation: For Python programs, it is frequently encouraged to use the ast.literal_eval() function instead of eval, since it is intentionally designed to avoid executing code. However, an adversary could still cause excessive memory or stack consumption via deeply nested structures [REF-1372], so the python documentation discourages use of ast.literal_eval() on untrusted data [REF-1373].
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-wj3h-wx8g-x699 H2O has an External Control of File Name or Path vulnerability | Critical | Also affects ai.h2o:h2o-core |
| GHSA-5w3j-gwgh-4rfv H2O affected by a deserialization vulnerability | Critical | Also affects ai.h2o:h2o-core |
| GHSA-g48v-3p35-88jr H2O Vulnerable to Arbitrary File Overwrite | High | Also affects ai.h2o:h2o-core |
| GHSA-5c8j-g96x-cj78 H2O Vulnerable to Denial of Service (DoS) via `HEAD` Request | High | Also affects ai.h2o:h2o-core |
| GHSA-p2vc-m5fv-9w9m H2O Vulnerable to Denial of Service (DoS) via `/3/ImportFiles` Endpoint | High | Also affects ai.h2o:h2o-core |
| GHSA-6w62-3jvj-mfj6 H2O Vulnerable to Denial of Service (DoS) via Large GZIP Parsing | High | Also affects ai.h2o:h2o-core |
| GHSA-m37h-8r48-2cxj H2O Vulnerable to Execution of Arbitrary Files | Medium | Also affects ai.h2o:h2o-core |
| GHSA-47f6-5p7h-5f3h H2O Vulnerable to Arbitrary File Overwrite via File Export | High | Also affects ai.h2o:h2o-core |
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