Bug 2553279 (CVE-2026-85748)

Summary: CVE-2026-85748 mariadb: mariadb: use-after-free in SYS_REFCURSOR during FETCH operations
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: eglynn, jjoyce, jpretori, jschluet, lhh, mburns, mgarciac, rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in MariaDB. An authenticated database user with low privileges can trigger a use-after-free memory corruption condition during cursor FETCH operations involving SYS_REFCURSOR. This flaw allows an attacker to corrupt memory and hijack program execution flow, potentially leading to privilege escalation and arbitrary code execution on the host system or causing a denial of service (DoS) by crashing the database server.
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Bug Depends On: 2554096    
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Description OSIDB Bzimport 2026-10-15 10:21:20 UTC 
A use-after-free vulnerability was found in MariaDB's SYS_REFCURSOR handling during FETCH operations. An authenticated, low-privileged SQL user can trigger a use-after-free condition that potentially allows control over a virtual function call. When chained with a separate information-disclosure vulnerability, this can be used to modify Security_context::master_access to obtain FILE privileges and subsequently achieve operating-system command execution through UDF loading.

The researcher reports successful exploitation against MariaDB 13.0.1-rc with ASLR, PIE, and Full RELRO enabled.

Reference: https://hackerone.com/reports/3856148