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

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.9 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS

• CVE-2026-55859: 0.49% estimated exploitation activity in the next 30 days; percentile 41.95 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary The connector encodes and decodes all character data assuming the connection character set is UTF-8. A server can change charactersetclient mid-session to a non-UTF-8 charset, after which the driver and server interpret the same bytes under different encodings, causing silent data corruption and a client/server charset-confusion mismatch. Details The driver encodes and decodes all character data on the assumption that the connection character set is UTF-8. The server can, however, announce a change of charactersetclient mid-session through the OK-packet session-state-tracking mechanism, for example via a SET NAMES … run by a stored routine or trigger, by server configuration, or by a hostile server. If the new charset is not UTF-8, the driver continues to read and write UTF-8 while the server interprets the same bytes under a different encoding. The result is silent data corruption and a client/server charset-confusion mismatch. Charset confusion of this kind is also the…

Published by the source

28 Aug 2026, 22:49 UTC

Last modified by the source

28 Aug 2026, 23:10 UTC

Source last checked

26 Oct 2026, 16:55 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-5rqc-86vf-g8r2

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-5rqc-86vf-g8r2

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# Patch Next advisory brief: CVE-2026-55859

Advisory: org.mariadb:r2dbc-mariadb has Inappropriate Encoding for Output Context and Improper Encoding or Escaping of Output
IDs: CVE-2026-55859, GHSA-5rqc-86vf-g8r2
Record: https://patchnext.com/advisories/cve-2026-55859 (revision 2, source checked 26 Oct 2026, 16:55 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: org.mariadb:r2dbc-mariadb 1.4.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven org.mariadb:r2dbc-mariadb: affected < 1.4.1; fixed in 1.4.1

## Suggested inspection (read-only)
- Maven org.mariadb:r2dbc-mariadb: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on org.mariadb:r2dbc-mariadb.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-5rqc-86vf-g8r2 (OSV record GHSA-5rqc-86vf-g8r2 lists affected ranges: Maven org.mariadb:r2dbc-mariadb >=0 <1.4.1 (fixed))
- Verified: https://github.com/advisories/GHSA-5rqc-86vf-g8r2 (GitHub-reviewed advisory GHSA-5rqc-86vf-g8r2 lists affected ranges: Maven org.mariadb:r2dbc-mariadb >=0 <1.4.1)

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