# org.mariadb:r2dbc-mariadb has Inappropriate Encoding for Output Context and Improper Encoding or Escaping of Output

Advisory record · `GHSA-5rqc-86vf-g8r2`

- **Identifiers:** `GHSA-5rqc-86vf-g8r2` · `CVE-2026-55859`
- **State:** Confirmed
- **Severity:** CVSS 5.9 Medium
- **Critical:** No
- **Weakness (CWE):** [CWE-116](https://cwe.mitre.org/data/definitions/116.html) · [CWE-838](https://cwe.mitre.org/data/definitions/838.html)
- **Tags:** [CWE-116](https://agentprime.io/advisories/tag/cwe-116.md) · [CWE-838](https://agentprime.io/advisories/tag/cwe-838.md)
- **Published:** 28 Aug 2026
- **Updated:** 28 Aug 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 28 Aug 2026, 22:49 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `org.mariadb:r2dbc-mariadb` (Maven): affected `<1.4.1`; fixed in `1.4.1`

## Machine-written summary

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

> Versions of org.mariadb:r2dbc-mariadb below 1.4.1 are affected. A hostile or man-in-the-middle server, or server-side state such as a stored routine or trigger, can switch the connection character set to a non-UTF-8 value mid-session, causing silent data corruption and a possible escaping bypass that can lead to SQL injection. Upgrade to 1.4.1 or later; the driver now rejects non-UTF-8 charset changes and closes the connection. No reliable workaround is given.

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

- 5.9 Medium, CVSS 3.1: `CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0049, the 42nd percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:19 UTC: First seen by agentprime
- 31 Oct 2026, 14:19 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-5rqc-86vf-g8r2)

## Sources

- [GitHub Advisory Database: GHSA-5rqc-86vf-g8r2](https://github.com/advisories/GHSA-5rqc-86vf-g8r2)
- [OSV: GHSA-5rqc-86vf-g8r2](https://osv.dev/vulnerability/GHSA-5rqc-86vf-g8r2)
- <https://github.com/mariadb-corporation/mariadb-connector-r2dbc/security/advisories/GHSA-5rqc-86vf-g8r2>
- <https://github.com/mariadb-corporation/mariadb-connector-r2dbc/commit/38bad9afebc6c581a853656a42f9ebf403b1b1b7>
- <https://github.com/mariadb-corporation/mariadb-connector-r2dbc>
- <https://github.com/mariadb-corporation/mariadb-connector-r2dbc/releases/tag/1.4.1>
- <https://jira.mariadb.org/browse/R2DBC-124>

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-5rqc-86vf-g8r2>, 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-5rqc-86vf-g8r2/>. Everything for agents: <https://agentprime.io/llms.txt>.