External risk intelligence

Perl DBI Heap Overflow in SQL Statement Preparsing

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2026-10879

A heap overflow vulnerability exists in Perl's DBI library, triggered when parsing SQL statements with over nine binders. This could allow for denial of service or potentially code execution in applications using this library for database interactions.

1Halo Surface Signal

Out-of-bounds Write

Perl Dbi

before 1.648

External exposure likelihood

Halo Surface Signal score for CVE-2026-10879

DBI is a database interface library/module used within applications, not a standalone network-facing service or appliance. It operates as an internal component or dependency during code execution; therefore, it is not directly reachable from the public internet in standard deployment patterns.

PCI scan relevance

PCI Relevance for CVE-2026-10879

Yes

CVE-2026-10879 — Halo PCI Relevance: Yes. Under typical PCI ASV external scan criteria, this issue may be flagged for scan prioritization.

This Perl DBI vulnerability allows remote attackers to cause a heap overflow during SQL statement preparsing, potentially impacting system availability and integrity.

Scan-prioritization guidance only—not a PCI DSS certification or ASV attestation.

Horizon Alert

Summary of the vulnerability and why it matters

A vulnerability has been identified in the DBI library for Perl, specifically affecting how SQL statements are prepared. This issue could allow for the overflow of a buffer, potentially leading to the compromise of systems that utilize this library for database interactions.

SQL statement preparation can be exploited.
It matters for systems using Perl database connectivity.
Confirm if your applications use this library.

Attack Path

How an attacker could exploit the issue

An attacker could exploit this vulnerability by sending specially crafted SQL statements to an application that uses a vulnerable version of the DBI library for Perl. The preparse method within DBI improperly handles the expansion of SQL placeholder characters, leading to a heap overflow when more than nine binders are used. This overflow could allow an attacker to cause a denial of service or potentially execute arbitrary code.

Network access to application.
Triggering SQL preparsing with many binders.
Denial of service or code execution.

Live Threat

Current exploitation, exposure, and threat context

When DBI for Perl improperly handles the preparsing of SQL statements with many binders, a heap overflow could occur. This may allow an attacker to disrupt or crash services that rely on this library, potentially impacting database operations.

Application stability and database access.
Malicious SQL statements could trigger overflow.
Denial of service to database operations.

Priority actions

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability in DBI affects Perl applications that parse SQL statements with more than nine binders. Application owners and platform teams are likely responsible for identifying and remediating this issue. The first practical step is to locate all instances of the affected DBI version, assess their reachability and criticality, and then plan remediation based on identified risk.

Application owners should prioritize remediation.
Verify DBI deployment and SQL binder usage.
Plan coordinated updates during maintenance.

Frequently asked questions

What is Perl DBI?

Perl DBI (Database Interface) is a standard database access module for the Perl programming language. It acts as a bridge, allowing Perl applications to communicate with various database engines—like MySQL, PostgreSQL, or SQLite—using a consistent set of commands. Developers rely on it to safely execute queries and manage data connections within their custom software and backend scripts.

What does CVE-2026-10879 mean by heap overflow?

This is a memory corruption flaw (CWE-787). When the DBI library prepares a SQL query, it reserves a specific amount of memory for placeholder variables. Because the code underestimates the space needed for queries with ten or more placeholders, it writes data past the end of the allocated memory buffer. This memory error can destabilize the application or, in some cases, allow unauthorized code execution.

How is the heap overflow in DBI triggered?

The flaw is triggered when an application processes a SQL statement containing ten or more placeholders (binders). If a query uses only nine or fewer binders, the current buffer allocation is sufficient, and the vulnerability is not triggered. The issue arises specifically during the 'preparse' phase, where the library attempts to expand these placeholders into a format required by the database.

Is my system at risk from CVE-2026-10879?

According to Halo Surface Signal, this risk is very unlikely for most systems because DBI is a library used inside applications, not a standalone service exposed to the internet. You are primarily at risk if you run custom Perl applications that accept and process untrusted or complex SQL queries from external users, as those inputs could potentially contain the specific binder patterns required to trigger the overflow.

What should I do if I use Perl DBI?

First, identify which applications in your environment utilize the DBI module and check their installed version. If you are running any version older than 1.648, plan an update to the latest release to receive the necessary patches. Before applying updates, verify if your SQL queries commonly use more than nine placeholders, as this will help you prioritize which applications require testing and remediation first.

References

Written by Nicholas Merritt

External-surface CVE analysis and Halo Surface Signal prioritization for Halo Threat Intelligence.