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Fencer Intel
high 8.8

CVE-2026-126197 json

pgEdge Postgres MCP Server SQL injection through custom pl-do tool parameters

published 4d ago modified yesterday also EUVD-2026-124568 , GHSA-r5pp-jx86-r6r9

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository pgEdge/pgedge-postgres-mcp. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 31%
public exploits
0
none known

Summary

pgEdge Postgres MCP Server enables SQL queries against PostgreSQL databases through Model Context Protocol compatible clients. Prior to 1.1.0, custom pl-do tools interpolated JSON arguments into a PostgreSQL DO block delimited by fixed dollar-quote tags. An argument containing $mcp_custom_tool$ could terminate the block and inject arbitrary SQL statements, while $mcp_args$ could inject procedural code into a plpgsql block. Because the statement used the simple query protocol, injected text could include additional statements and transaction control, bypassing read_only and accessing data or modifying resources available to the connecting role. The issue requires at least one pl-do custom tool; sql and pl-func tools pass arguments as bind parameters and are not affected by this injection mechanism. This issue is fixed in 1.1.0.

Patch / fix

Is CVE-2026-126197 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
yesterday

Exploit prediction

0.37% chance of exploitation in the next 30 days, higher than 31% of all scored CVEs (FIRST EPSS, 2026-11-14).

CVSS scores

assigned by version score vector
CNA 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • pgEdge pgedge-postgres-mcp

Classification

Weakness
  • CWE-89 Improper Neutralization of Special Elements used in an SQL Command

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of pgEdge/pgedge-postgres-mcp published their own advisory on GitHub. Reviewed sources take precedence over it.