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Set UserApplication · Set User Project

CVE-2021-41558

CRITICAL · 9.8 CVSS v3.1 Published 2021-09-27
Fix available
A fix is available. Upgrade to 3.0.0 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
The set_user extension module before 3.0.0 for PostgreSQL allows ProcessUtility_hook bypass via set_config.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The set_user PostgreSQL extension before version 3.0.0 contains a vulnerability allowing the set_config function to bypass the ProcessUtility_hook security control. This enables an attacker to circumvent role-based access restrictions and potentially escalate privileges or modify PostgreSQL configuration settings unexpectedly.

MitigationUpgrade the set_user extension to version 3.0.0 or later to resolve the ProcessUtility_hook bypass vulnerability.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Set UserApplication
Affected:< 3.0.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check if set_user extension is installed
    Query the pg_extensions system catalog: SELECT extname, extversion FROM pg_extension WHERE extname = 'set_user';
    Affected if No rows returned means the extension is not installed and not affected
  2. Determine installed set_user version
    Run: SELECT extname, extversion FROM pg_extension WHERE extname = 'set_user'; Compare the extversion value to the affected range (less than 3.0.0).
    Affected if The extversion is less than 3.0.0 (e.g., 2.x.x, 1.x.x)
  3. Verify set_config function is accessible
    Check if untrusted users have access to set_config within set_user-protected sessions by reviewing GRANT statements on the set_config function and any set_user role configurations.
    Affected if Untrusted roles have execute permission on set_config while using set_user protection
  4. Check for ProcessUtility_hook usage
    Review postgresql.conf for any custom ProcessUtility_hook configurations and verify if set_user is loaded in shared_preload_libraries.
    Affected if set_user is in shared_preload_libraries and the extension version is below 3.0.0

A user is affected if the set_user extension is installed with a version lower than 3.0.0 and is loaded via shared_preload_libraries, allowing set_config to bypass security controls.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 3.0.0 or later
Fixed in 3.0.0
Interim mitigation

Upgrade the set_user extension to version 3.0.0 or later to resolve the ProcessUtility_hook bypass vulnerability.

Recommended fix High confidence

set_user version 3.0.0

  1. Check the currently installed set_user extension version using: SELECT * FROM pg_available_extensions WHERE name = 'set_user';
  2. Stop PostgreSQL or ensure no active sessions using the set_user extension.
  3. Upgrade the set_user extension to version 3.0.0 or later. For package-managed systems, use: apt-get update && apt-get install postgresql-13-set-user (or appropriate version). For source installations, download and compile version 3.0.0 or later from the PostgreSQL SET USER extension repository.
  4. Restart PostgreSQL to load the new extension version.
  5. Verify the upgrade by running: SELECT extversion FROM pg_extension WHERE extname = 'set_user';
  6. Ensure the extension is updated in the database by running: ALTER EXTENSION set_user UPDATE TO '3.0.0';
  7. Test that the extension functions correctly and the vulnerability is mitigated.
Caveat Review the release notes for 3.0.0 to check for any configuration or behavioral changes that may affect existing setups

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Set User Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-41558 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data