c3p0: Improper Control of Generation of Code
CVE-2026-27830 is a high-severity improper control of generation of code vulnerability in c3p0 from Swaldman, with a CVSS 3.1 base score of 8.0 out of 10. It can be exploited from the same local network by an attacker with a low-privileged account, without any action from a user. Affected c3p0 versions: < 0.12.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.6% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of c3p0 you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
Affected products and versions
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- AdjacentThe attacker must be on the same local network segment.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.9 | High | CNA (github.com) |
| CVSS 3.1 | 8.0 | High | CNA |
Official description
c3p0, a JDBC Connection pooling library, is vulnerable to attack via maliciously crafted Java-serialized objects and `javax.naming.Reference` instances. Several c3p0 `ConnectionPoolDataSource` implementations have a property called `userOverridesAsString` which conceptually represents a `Map<String,Map<String,String>>`. Prior to v0.12.0, that property was maintained as a hex-encoded serialized object. Any attacker able to reset this property, on an existing `ConnectionPoolDataSource` or via maliciously crafted serialized objects or `javax.naming.Reference` instances could be tailored execute unexpected code on the application's `CLASSPATH`. The danger of this vulnerability was strongly magnified by vulnerabilities in c3p0's main dependency, mchange-commons-java. This library includes code that mirrors early implementations of JNDI functionality, including ungated support for remote `factoryClassLocation` values. Attackers could set c3p0's `userOverridesAsString` hex-encoded serialized objects that include objects "indirectly serialized" via JNDI references. Deserialization of those objects and dereferencing of the embedded `javax.naming.Reference` objects could provoke download and execution of malicious code from a remote `factoryClassLocation`. Although hazard presented by c3p0's vulnerabilites are exarcerbated by vulnerabilities in mchange-commons-java, use of Java-serialized-object hex as the format for a writable Java-Bean property, of objects that may be exposed across JNDI interfaces, represents a serious independent fragility. The `userOverridesAsString` property of c3p0 `ConnectionPoolDataSource` classes has been reimplemented to use a safe CSV-based format, rather than rely upon potentially dangerous Java object deserialization. c3p0-0.12.0+ and above depend upon mchange-commons-java 0.4.0+, which gates support for remote `factoryClassLocation` values by configuration parameters that default to restrictive values. c3p0 additionally enforces the new mchange-commons-java `com.mchange.v2.naming.nameGuardClassName` to prevent injection of unexpected, potentially remote JNDI names. There is no supported workaround for versions of c3p0 prior to 0.12.0.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Control of Generation of Code
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 developers prevent this class of flaw
- Refactor your program so that you do not have to dynamically generate code.
- 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.
- 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.
More Improper Control of Generation of Code vulnerabilities (CWE-94)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other references
- mogwailabs.de/en/blog/2025/02/c3p0-you-little-rascal
- mchange.com/projects/c3p0/#configuring_security
- mchange.com/projects/c3p0/#security-note
- access.redhat.com/errata/RHSA-2026:18054
- access.redhat.com/errata/RHSA-2026:18055
- access.redhat.com/errata/RHSA-2026:18059
- access.redhat.com/errata/RHSA-2026:28385
- access.redhat.com/errata/RHSA-2026:3890
- access.redhat.com/errata/RHSA-2026:4285
- access.redhat.com/security/cve/CVE-2026-27830
- bugzilla.redhat.com/show_bug.cgi?id=2442908
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-27830.json
Recent Improper Control of Generation of Code vulnerabilities
- 9.8 Critical severity
- 9.9 Critical severity
- 9.9 Critical severity
- 8.8 High severity
- 9.9 Critical severity
- 9.0 Critical severity
Spotted an error? Tell us.