CVE-2026-16241
Received Received - Intake

Integer Underflow in PostgreSQL ECPG Leads to DoS

Publication date: 2026-08-13

Last updated on: 2026-08-13

Assigner: PostgreSQL

Description
Integer underflow in PostgreSQL ECPG allows a database server administrator to achieve temporary denial of service against the ECPG client via sending a bytea value lacking the mandatory prefix. The client overwrites a huge memory region with bytes outside attacker knowledge or control. This typically yields a simple SIGSEGV, but rare cases might achieve client-specific integrity impact via the write. Versions before PostgreSQL 18.5, 17.11, 16.15, 15.19, and 14.24 are affected.

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Meta Information

Published
2026-08-13
Last Modified
2026-08-13
Generated
2026-08-13
AI Q&A
2026-08-13
EPSS Evaluated
N/A
NVD
CVE-2026-16241
EUVD
EUVD-2026-57850

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
postgresql postgresql to 18.5|end_excluding=17.11|end_excluding=16.15|end_excluding=15.19|end_excluding=14.24 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-191 The product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result.

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Executive Summary

This vulnerability is an integer underflow in PostgreSQL's ECPG that allows a database server administrator to cause a temporary denial of service against the ECPG client. It occurs when a bytea value without the required prefix is sent, causing the client to overwrite a large memory region with uncontrolled data, typically leading to a crash (SIGSEGV). Rare cases might allow for client-specific integrity impacts.

Detection Guidance

Detecting this vulnerability requires checking PostgreSQL version and ECPG client behavior. Use 'postgres --version' or 'psql --version' to verify if your PostgreSQL version is below 18.5, 17.11, 16.15, 15.19, or 14.24. Monitor client crashes or SIGSEGV errors when processing bytea values without prefixes.

Impact Analysis

The primary impact is a temporary denial of service where the ECPG client crashes due to a segmentation fault. In rare cases, it might allow for client-specific integrity impacts, such as unauthorized data modification, but this is not the typical outcome.

Compliance Impact

This vulnerability could potentially impact compliance by causing data integrity issues or service disruptions, which may violate requirements for data availability and integrity in standards like GDPR or HIPAA. However, the primary impact is denial of service, so compliance impact depends on specific use cases and mitigations.

Mitigation Strategies

Upgrade PostgreSQL to version 18.5, 17.11, 16.15, 15.19, or 14.24 or later immediately. Apply the official patches released on August 13, 2026. Restrict database server administrator privileges to reduce attack surface.

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