dbcve.org
PostgreSQLDatabase / datastore

CVE-2021-3677

MEDIUM · 6.5 CVSS v3.1 Published 2022-03-02
Fix available
A fix is available. Upgrade to 11.13 / 12.8 or later.
See remediation →
71/100
Remediation priority · Elevated
Remotely reachable 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
A flaw was found in postgresql. A purpose-crafted query can read arbitrary bytes of server memory. In the default configuration, any authenticated database user can complete this attack at will. The attack does not require the ability to create objects. If server settings include max_worker_processes=0, the known versions of this attack are infeasible. However, undiscovered variants of the attack may be independent of that setting.

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

PostgreSQL contains a flaw allowing authenticated database users to read arbitrary bytes of server memory via specially crafted queries. In default configurations, any authenticated user can exploit this without requiring special permissions such as the ability to create objects.

MitigationApply PostgreSQL vendor patches or set max_worker_processes=0 in postgresql.conf to mitigate known attack variants (note: this setting may have availability implications and undiscovered variants may still work).

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
PostgreSQLDatabase / datastore
Affected:>= 11.0, < 11.13>= 12.0, < 12.8>= 13.0, < 13.4
VirtualizationApplication
Affected:= 4.0
Enterprise LinuxOperating system
Affected:= 8.0
Enterprise Linux For Ibm Z SystemsOperating system
Affected:= 8.0
Enterprise Linux For Power Little EndianOperating system
Affected:= 8.0
Software CollectionsApplication
Affected:= 1.0
FedoraOperating system
Affected:= 34

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

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

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. Identify installed PostgreSQL version
    Run 'psql --version' or connect to the database and run 'SELECT version();'
    Affected if The version number is >= 11.0 and < 11.13, OR >= 12.0 and < 12.8, OR >= 13.0 and < 13.4
  2. Verify database authentication is enabled
    Check pg_hba.conf file or confirm user connections are allowed to the database
    Affected if Users can authenticate to the database (this is the default state in most PostgreSQL installations)
  3. Confirm the database accepts user connections
    Attempt to connect to the database as any standard user or check that pg_stat_activity shows active user sessions
    Affected if Any authenticated user can connect to the database (the vulnerability requires only a database user, not superuser)
  4. Check for exposed PostgreSQL service
    Identify if port 5432 (default) is accessible externally or if the database is exposed via network
    Affected if The PostgreSQL port is accessible to untrusted users who have valid database credentials

A user is affected if their PostgreSQL version falls within the vulnerable ranges and any authenticated database user can connect to the database.

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 11.13 / 12.8 / 13.4 or later
Fixed in 11.1312.813.4
Interim mitigation

Apply PostgreSQL vendor patches or set max_worker_processes=0 in postgresql.conf to mitigate known attack variants (note: this setting may have availability implications and undiscovered variants may still work).

Recommended fix High confidence

PostgreSQL 11.13, 12.8, or 13.4 (depending on your current major version)

  1. Identify your current PostgreSQL version using: psql -V or SELECT version();
  2. For PostgreSQL 11.x users: Upgrade to version 11.13 or later (recommended: 11.13, or jump to 12.8/13.4 for additional fixes)
  3. For PostgreSQL 12.x users: Upgrade to version 12.8 or later (recommended: 12.8, or jump to 13.4 for additional fixes)
  4. For PostgreSQL 13.x users: Upgrade to version 13.4 or later
  5. After upgrade, verify the new version: psql -V
  6. Test your application functionality against the upgraded database before deploying to production
Caveat PostgreSQL minor version upgrades are typically backward-compatible; review release notes for any behavior changes

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

Fix this in PostgreSQL Scoped from the published advisory
  • Consultation3.0 h
  • Implementation3.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,770
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,832.

Scan for this in your stack

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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-2021-3677 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