Overview
A critical security vulnerability, identified as CVE-2025-12818, has been discovered in the PostgreSQL libpq client library. This integer wraparound vulnerability can lead to an out-of-bounds write, potentially causing a segmentation fault and impacting the stability of applications using the affected libpq versions. It’s crucial to update your PostgreSQL installations to a patched version as soon as possible.
Technical Details
The vulnerability stems from an integer wraparound in multiple functions within the libpq client library. Specifically, when processing input from an application or a network peer, libpq can incorrectly calculate the size of a memory allocation. This occurs because the input values, intended to represent the length of data to be processed, can wrap around, resulting in a significantly smaller allocation than required. Subsequently, when data is written to this undersized buffer, it overflows into adjacent memory regions by potentially hundreds of megabytes, leading to an out-of-bounds write. This overflow often results in a segmentation fault, crashing the application using libpq.
CVSS Analysis
This vulnerability has been assigned a CVSS score of 5.9, classifying it as MEDIUM severity.
- CVSS Score: 5.9
- Vector: (Details unavailable without the full CVSS vector string)
While the vulnerability requires either a malicious application input provider or compromised network peer to trigger, the potential for denial-of-service through application crashes makes it a significant concern. Exploitation leading to arbitrary code execution is possible but complex and dependent on the specific environment and application.
Possible Impact
The primary impact of CVE-2025-12818 is a denial-of-service condition due to segmentation faults in applications using the vulnerable libpq library. A malicious actor controlling either the application input or the network communication could trigger the vulnerability, causing applications to crash. While directly escalating privileges or achieving arbitrary code execution is less straightforward, the memory corruption introduced by the out-of-bounds write could potentially be leveraged for more sophisticated attacks in certain scenarios. The impact severity is increased if the PostgreSQL client is used by a critical application or service.
Mitigation and Patch Steps
The recommended mitigation is to upgrade your PostgreSQL installation to one of the following versions or later:
- PostgreSQL 18.1
- PostgreSQL 17.7
- PostgreSQL 16.11
- PostgreSQL 15.15
- PostgreSQL 14.20
- PostgreSQL 13.23
If upgrading is not immediately feasible, consider implementing network-level access controls to restrict connections to your PostgreSQL database. Additionally, carefully scrutinize application inputs and network traffic for suspicious patterns that might indicate an attempt to exploit this vulnerability. While not a complete solution, input validation can help reduce the likelihood of triggering the integer wraparound.