CVE-2026-85746: MariaDB: Out-of-bound buffer write on in `ST_AsText` of nested GeometryCollections

Severity: critical (CVSS 9.9 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-16 · updated 2026-10-20
Weakness: CWE-787

Description

MariaDB server is a community developed fork of MySQL server. From 10.6.1 until 10.6.28, 10.11.19, 11.4.13, 11.8.9, 12.3.3, and 13.0.2, ST_AsText can write beyond an allocated output buffer when converting deeply nested GeometryCollections because recursive WKT serialization does not account for bytes consumed or reserve sufficient space. A low-privileged remote attacker can submit a specially crafted GIS object to corrupt memory and potentially achieve code execution when combined with another vulnerability. This issue is fixed in versions 10.6.28, 10.11.19, 11.4.13, 11.8.9, 12.3.3, and 13.0.2.

Affected products

MariaDB: from 10.6.1 before 10.6.28; from 10.11.1 before 10.11.19; from 11.4.1 before 11.4.13; from 11.8.1 before 11.8.9; from 12.3.1 before 12.3.3; 13.0.1 (and their updates) — fixed in 10.6.28, 10.11.19, 11.4.13, 11.8.9, 12.3.3

How to fix

Upgrade to a fixed version: MariaDB 10.6.28, 10.11.19, 11.4.13, 11.8.9. Check the vendor advisory for mitigations.

References

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