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CVE-2026-17351 — The fix for CVE-2026-12045 in pgAdmin 4 9.16 required the LLM-supplied query passed to…

Key facts

CVE-2026-17351 is a Critical (9.0) vulnerability: The fix for CVE-2026-12045 in pgAdmin 4 9.16 required the LLM-supplied query passed to…. This entry ships a detection-only PoC and a Docker test lab.
CVE CVE-2026-17351
Severity Critical (9.0)
Detection / prevention —
PoC poc.py
Source 2026/CVE-2026-17351/

Details

English | 한국어

Description

The fix for CVE-2026-12045 in pgAdmin 4 9.16 required the LLM-supplied query passed to the AI Assistant's execute_sql_query tool to parse, via sqlparse, as exactly one non-transaction-control statement before running it inside a BEGIN TRANSACTION READ ONLY wrapper. sqlparse's string-literal lexing can disagree with PostgreSQL's own parser: under standard_conforming_strings = on (PostgreSQL's default since 9.1), a backslash immediately before a quote is an ordinary character to PostgreSQL, but sqlparse treats it as escaping the quote. A payload such as SELECT '\';COMMIT;CREATE TABLE pwn(x int);SELECT 1 --' therefore parses as a single SELECT to sqlparse's validator, while PostgreSQL executes it as four statements: the smuggled COMMIT ends the wrapping read-only transaction, and the trailing ROLLBACK becomes a no-op. This reintroduces the same write/RCE bypass CVE-2026-12045 was meant to close, reachable via the same indirect prompt-injection delivery (an attacker plants the payload in any object the AI Assistant may read; the LLM emits it as a tool call).

An initial candidate fix ran the query with psycopg's execute(..., prepare=True), intending to force PostgreSQL's own Parse step (extended query protocol) to reject multi-statement text regardless of sqlparse's classification. This candidate fix does not work as submitted: psycopg3's PrepareManager silently ignores the prepare argument whenever the connection's prepare_threshold is None, which is pgAdmin's default for every server connection (the per-server "Prepare threshold" field is blank unless an administrator explicitly sets it) -- psycopg3 falls back to the simple query protocol, the same multi-statement-capable path the bypass exploits, so the candidate fix closes nothing on any real-world default configuration.

The corrected fix sets conn.prepare_threshold = 0 directly on the dedicated, single-use read-only connection the AI Assistant tool opens, structurally forcing the extended query protocol independent of any server-level configuration. Verified against a live PostgreSQL 18 instance: the payload executes successfully under the prepare_threshold=None (default) behavior, and is rejected with "cannot insert multiple commands into a prepared statement" once prepare_threshold=0 is set on that connection.

This issue affects pgAdmin 4: from 9.13 before 9.17.

Vulnerability Details

Property Value
CVE ID CVE-2026-17351
Type SQLI
CVSS Score 9.0

Proof of Concept

Download

# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2026/CVE-2026-17351/poc.py

Usage

# Run PoC against target
python3 poc.py --target <TARGET_URL>

# With authentication
python3 poc.py --target <TARGET_URL> --username <USER> --password <PASS>

⚠️ Warning: This PoC is for authorized security testing only. It uses detection-only techniques and does not exploit or damage target systems.

Test Lab

This repository includes a Docker-based test environment with both vulnerable and patched applications.

Quick Start

# Clone and navigate to CVE directory
cd CVE-2026-17351

# Start both applications
docker-compose up -d

# Run tests
./run-tests.sh    # Linux/Mac
./run-tests.ps1   # Windows PowerShell

Application Endpoints

Application URL Status
Vulnerable App http://localhost:8080 Shows vulnerability
Patched App http://localhost:8081 Demonstrates fix

Directory Structure

├── README.md           # English documentation
├── README_KO.md        # Korean documentation
├── poc.py              # PoC detection script
├── docker-compose.yml  # Container orchestration
├── run-tests.sh        # Linux/Mac test runner
├── run-tests.ps1       # Windows test runner
├── vulnerable-app/     # Vulnerable version
│   ├── app.py
│   ├── Dockerfile
│   └── requirements.txt
└── patched-app/        # Fixed version
    ├── app.py
    ├── Dockerfile
    └── requirements.txt

References

  • https://github.com/pgadmin-org/pgadmin4/commit/bf4792444446f0e7ab721d23cbd6bfe6afaa7a8b
  • https://github.com/pgadmin-org/pgadmin4/commit/ef76102bcd1cdb544eb9b4ef18d3382f22b76752
  • https://github.com/pgadmin-org/pgadmin4/issues/10192

Generated by PoC Generator on 2026-08-01T18:11:03.499362285

Frequently asked questions

What is CVE-2026-17351?

CVE-2026-17351 is a Critical (9.0) vulnerability: The fix for CVE-2026-12045 in pgAdmin 4 9.16 required the LLM-supplied query passed to…. This entry ships a detection-only PoC and a Docker test lab.

How do I detect CVE-2026-17351?

Run the detection-only PoC included with this entry against your Docker test lab to confirm whether a target is affected; pair it with your own IDS logging.

How do I block or mitigate CVE-2026-17351?

Upgrade to a fixed version per the vendor advisory; the NVD record lists the affected versions. Use the included PoC to verify your remediation.

For authorized security testing and research only. See the full source and NVD record.