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A critical SQL injection vulnerability, identified as CVE-2026-31871, exists in Parse Server versions prior to 8.6.31 and 9.6.0-alpha.5 when using a PostgreSQL database . The flaw resides in how the PostgreSQL storage adapter processes `Increment` operations on nested object fields using dot notation (e.g., stats.counter). Specifically, the sub-key name following the dot is interpolated directly into SQL string literals without proper escaping or sanitization . An attacker with the ability to send write requests to the Parse Server REST API can craft a malicious sub-key name containing SQL syntax, such as single quotes, to break out of the intended string literal . This allows the attacker to append arbitrary SQL commands to the database query. Successful exploitation could lead to unauthorized reading or modification of data, execution of database commands, and a complete bypass of Class-Level Permissions (CLPs) and Access Control Lists (ACLs) . The vulnerability is specific to PostgreSQL deployments, as other databases like MongoDB are not affected by this particular injection point . The issue has been patched in versions 8.6.31 and 9.6.0-alpha.5 by escaping single quotes in the sub-key name before it is incorporated into the SQL query .
DailyCVE Form:
Platform: Parse Server
Version: <8.6.31, >=9.0.0-<9.6.0-alpha.5
Vulnerability : SQL Injection
Severity: Critical (CVSS:4.0 9.3)
Date: March 11, 2026
Prediction: Patched versions already released
What Undercode Say:
Analytics:
This vulnerability is critical due to its low attack complexity and network-based vector, requiring no privileges or user interaction . The CVSSv4 base score of 9.3 reflects the high potential impact on data confidentiality, integrity, and availability . Given that the flaw exists in a core database operation and can be triggered via the standard REST API, it is likely to be actively targeted. The bypass of CLPs and ACLs is particularly severe, as it undermines the primary security model of Parse Server applications. Only PostgreSQL backends are at risk, narrowing the affected user base but posing a grave threat to those that are vulnerable.
Exploit:
An attacker would send a crafted `Increment` operation to the REST API. The vulnerability is triggered by manipulating the sub-key in a dot-notation field. For example, a request targeting a field like `”stats.counter”` is vulnerable. By injecting a single quote and SQL payload into the sub-key name (the part after the dot), an attacker can alter the database query.
Conceptual Payload:
{
"stats.counter' ; --": {
"__op": "Increment",
"amount": 1
}
}
In this example, `counter’ ; –` is the malicious sub-key. When interpolated into the SQL query, the single quote would close the string literal, allowing the attacker to inject and execute arbitrary SQL commands (;) and then comment out (--) the rest of the original query to prevent syntax errors.
Protection from this CVE:
The primary protection is to upgrade Parse Server to a patched version: 8.6.31 or 9.6.0-alpha.5 (or later) . The official patch fixes the vulnerability by escaping single quotes in the sub-key name before it is used in the SQL string literal.
Example of the Fix (Conceptual Code Snippet):
// Vulnerable code (simplified)
const subKey = request.subKey; // e.g., "counter' ; --"
const sql = <code>UPDATE table SET "${subKey}" = "${subKey}" + 1 WHERE ...</code>;
// Patched code (simplified)
const subKey = request.subKey;
const escapedSubKey = subKey.replace(/'/g, "''"); // Escape single quotes
const sql = <code>UPDATE table SET "${escapedSubKey}" = "${escapedSubKey}" + 1 WHERE ...</code>;
There is no known workaround for this vulnerability, making upgrading the only secure option .
Impact:
Successful exploitation of CVE-2026-31871 allows an unauthenticated attacker to execute arbitrary SQL commands on the PostgreSQL database . This can lead to:
Complete data breach: Reading all data stored in the database, including user credentials, personal information, and application secrets.
Data manipulation and destruction: Modifying or deleting any data, corrupting the application’s state.
Privilege escalation: Gaining administrative access to the Parse Server application by directly manipulating the database to alter role assignments or user permissions .
Potential host compromise: Depending on database permissions, an attacker might be able to execute operating system commands, leading to full server takeover .
Complete bypass of application security: All Class-Level Permissions (CLPs) and Access Control Lists (ACLs) enforced by Parse Server are rendered useless, as the attacker operates directly on the database .
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Sources:
Reported By: github.com
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