SQL Injection in PostgreSQL
CVE-2026-6637
Stack buffer overflow in PostgreSQL module "refint" allows an unprivileged database user to execute arbitrary code as the operating system user running the database. A distinct attack is possible if the application declares a user-controlled column as a "refint" cascade primary key and facilitates user-controlled updates to that column. In that case, a SQL injection allows a primary key update value provider to execute arbitrary SQL as the database user performing the primary key update. Versions before PostgreSQL 18.4, 17.10, 16.14, 15.18, and 14.23 are affected.
Vulnerability class: SQL Injection
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.004 (28.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 28th percentile — 28.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
- PostgreSQL
- PostgreSQL — versions 18, 17, 16
Weakness classification (CWE)
References
- f86ef6dc-4d3a-42ad-8f28-e6d5547a5007 (Patch, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-6637?
- CVE-2026-6637 is a high-severity vulnerability in PostgreSQL, classified under SQL Injection. CVSS score: 8.8/10. Published 2026-05-14.
- How severe is CVE-2026-6637?
- High severity. CVSS v3 base score is 8.8 out of 10.