# c3p0 vulnerable to Remote Code Execution via unsafe deserialization of userOverridesAsString property

Advisory record · `GHSA-5476-xc4j-rqcv`

- **Identifiers:** `GHSA-5476-xc4j-rqcv` · `CVE-2026-27830`
- **State:** Confirmed
- **Severity:** CVSS 8.9 High
- **Critical:** No
- **Weakness (CWE):** [CWE-94](https://cwe.mitre.org/data/definitions/94.html) · [CWE-502](https://cwe.mitre.org/data/definitions/502.html)
- **Tags:** [Code injection](https://agentprime.io/advisories/tag/code-injection.md) · [Insecure deserialization](https://agentprime.io/advisories/tag/deserialization.md)
- **Published:** 25 Feb 2026
- **Updated:** 10 Sept 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 25 Feb 2026, 18:35 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `com.mchange:c3p0` (Maven): affected `<0.12.0`; fixed in `0.12.0`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> Remote code execution is possible in the Maven package com.mchange:c3p0 before 0.12.0. An attacker who can reset the userOverridesAsString property on a ConnectionPoolDataSource, or supply maliciously crafted serialized objects or JNDI references, can execute unexpected code on the application's classpath. Upgrade to c3p0 0.12.0 or later; no workaround is supported for earlier versions.

Written 2 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 8.9 High, CVSS 4.0: `CVSS:4.0/AV:A/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0060, the 48th percentile, on 12 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:17 UTC: First seen by agentprime
- 31 Oct 2026, 14:17 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-5476-xc4j-rqcv)

## Sources

- [GitHub Advisory Database: GHSA-5476-xc4j-rqcv](https://github.com/advisories/GHSA-5476-xc4j-rqcv)
- [OSV: GHSA-5476-xc4j-rqcv](https://osv.dev/vulnerability/GHSA-5476-xc4j-rqcv)
- <https://github.com/swaldman/c3p0/security/advisories/GHSA-5476-xc4j-rqcv>
- <https://nvd.nist.gov/vuln/detail/CVE-2026-27830>
- <https://github.com/swaldman/c3p0/commit/e14cbd8166e423e2e9a9d6f08b2add3433492d6e>
- <https://github.com/swaldman/c3p0>
- <https://mogwailabs.de/en/blog/2025/02/c3p0-you-little-rascal>
- <https://www.mchange.com/projects/c3p0/#configuring_security>
- <https://www.mchange.com/projects/c3p0/#security-note>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-5476-xc4j-rqcv>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-5476-xc4j-rqcv/>. Everything for agents: <https://agentprime.io/llms.txt>.