CVE-2026-76240 Overview
CVE-2026-76240 is a SQL injection vulnerability [CWE-89] in stigmem-node version 0.9.0a1. The library interpolates Postgres backend schema identifiers directly into SQL strings without defensive quoting or validation. In the affected code path the schema value is operator-controlled, but the unsafe pattern permits SQL injection if the schema name is ever derived from tenant, request, or user input. The maintainers released version 0.9.0a2, which adds identifier quoting and input validation.
Critical Impact
An attacker who can influence the Postgres schema identifier can execute arbitrary SQL against the backend database, compromising the confidentiality, integrity, and availability of stored data.
Affected Products
- stigmem-node version 0.9.0a1
- Deployments that source the Postgres schema name from tenant, request, or user-controlled input
- Applications using the affected Postgres backend code path prior to 0.9.0a2
Discovery Timeline
- 2026-08-19 - CVE-2026-76240 published to NVD
- 2026-08-20 - Last updated in NVD database
Technical Details for CVE-2026-76240
Vulnerability Analysis
The vulnerability resides in the Postgres backend of stigmem-node0.9.0a1. The affected code path builds SQL statements by interpolating the schema identifier into query strings. The routine does not apply identifier quoting, escape untrusted characters, or validate the schema name against an allowlist of Postgres identifier syntax.
By default the schema value is set by the operator through deployment configuration, which reduces exposure in typical deployments. The unsafe pattern still creates risk in multi-tenant architectures where the schema is selected per tenant, or in any deployment that derives the schema name from HTTP requests, headers, or user input. In those configurations, an attacker can inject SQL fragments through the schema parameter and have them concatenated into executed queries.
Successful exploitation can read or modify arbitrary tables in the connected Postgres instance, subject to the database privileges granted to the application role. The vulnerability is classified under CWE-89: Improper Neutralization of Special Elements used in an SQL Command.
Root Cause
SQL identifiers in Postgres cannot be parameterized through prepared statements. Developers must therefore quote and validate identifiers manually. The affected code path skips both steps and inserts the schema string directly into query text, treating a structural SQL element as if it were trusted data.
Attack Vector
Exploitation requires that the schema identifier reach the vulnerable code path from a source the attacker can influence. This includes tenant lookups keyed by hostname, request bodies, query parameters, or configuration files editable by lower-privilege users. Once the tainted identifier is interpolated, standard SQL injection primitives apply, including UNION-based data extraction and stacked statements.
Refer to the GitHub Security Advisory and the VulnCheck SQL Injection Advisory for additional technical detail.
Detection Methods for CVE-2026-76240
Indicators of Compromise
- Postgres server logs showing unexpected statements referencing multiple schemas or containing SQL metacharacters such as ", ;, or -- in identifier positions.
- Application logs where the configured schema value contains whitespace, quotes, or SQL keywords.
- Errors from the Postgres parser indicating malformed identifiers originating from stigmem-node query paths.
Detection Strategies
- Inventory all deployments of stigmem-node and confirm the installed version; flag any instance at 0.9.0a1 or earlier.
- Perform static review of application code that sets the stigmem-node schema value and trace the data flow back to its source.
- Enable Postgres statement logging on affected databases and search for queries where the schema identifier does not match the expected allowlist.
Monitoring Recommendations
- Forward Postgres and application logs to a centralized analytics platform and alert on queries containing suspicious identifier content.
- Monitor for anomalous query volume or cross-schema access originating from the stigmem-node database role.
- Track outbound data volumes from the Postgres host to detect bulk extraction attempts.
How to Mitigate CVE-2026-76240
Immediate Actions Required
- Upgrade stigmem-node to version 0.9.0a2 or later, which adds identifier quoting and validation.
- Audit deployments to confirm the schema name is sourced only from trusted deployment configuration, not from tenant or request input.
- Rotate any Postgres credentials used by stigmem-node if logs show evidence of injection attempts.
Patch Information
The fix ships in stigmem-node0.9.0a2. The release quotes Postgres identifiers using safe delimiters and validates schema names before use. See the GitHub Security Advisory for the full patch reference.
Workarounds
- Configure the schema identifier only from trusted deployment configuration files controlled by operators.
- Restrict the Postgres role used by stigmem-node to the minimum required schemas and privileges.
- Add an application-layer allowlist that rejects any schema value not matching a strict [A-Za-z_][A-Za-z0-9_]* pattern.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
