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AuthoritativeApplication · Powerdns

CVE-2020-24698

CRITICAL · 9.8 CVSS v3.1 Published 2020-10-02
Fix available
A fix is available. Upgrade to after 4.3.0 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
An issue was discovered in PowerDNS Authoritative through 4.3.0 when --enable-experimental-gss-tsig is used. A remote, unauthenticated attacker might be able to cause a double-free, leading to a crash or possibly arbitrary code execution. by sending crafted queries with a GSS-TSIG signature.

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

PowerDNS Authoritative Server through 4.3.0 contains a double-free vulnerability in the experimental GSS-TSIG feature. A remote, unauthenticated attacker can trigger this via crafted queries containing malicious GSS-TSIG signatures, potentially causing server crashes or arbitrary code execution.

MitigationEither disable the experimental GSS-TSIG feature (rebuild without --enable-experimental-gss-tsig) or upgrade to PowerDNS Authoritative 4.3.1 or later which contains the patched fix.

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
AuthoritativeApplication
Affected:<= 4.3.0

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 PowerDNS Authoritative version
    Run `pdns_server --version` or `pdns --version` to identify the installed version
    Affected if Version is 4.3.0 or earlier (any version <= 4.3.0)
  2. Confirm GSS-TSIG feature was compiled in
    Run `pdns_server --version` or check binary for experimental-gss-tsig compile flag. Also check if the gss-tsig module exists in the module directory
    Affected if GSS-TSIG support is present in the binary (not available in builds without --enable-experimental-gss-tsig)
  3. Inspect PowerDNS configuration for GSS-TSIG settings
    Examine the pdns.conf configuration file for directives such as `gss-tsig` enablement, `module-dir` loading a gss-tsig module, or any `tsig-` prefixed keys referencing GSS
    Affected if GSS-TSIG is explicitly enabled or a GSS-TSIG key is configured in the configuration file
  4. Check for active GSS-TSIG TSIG keys
    Search configuration files for TSIG keys defined with GSSAPI provider type, or check runtime configuration via `pdns_control list all` for gss-tsig related zones or keys
    Affected if Any GSS-TSIG keys are defined or active on the server

A server is affected if it runs PowerDNS Authoritative version 4.3.0 or earlier AND has the experimental GSS-TSIG feature compiled in AND GSS-TSIG is configured or enabled.

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 a release after 4.3.0
Interim mitigation

Either disable the experimental GSS-TSIG feature (rebuild without --enable-experimental-gss-tsig) or upgrade to PowerDNS Authoritative 4.3.1 or later which contains the patched fix.

Recommended fix High confidence

PowerDNS Authoritative 4.3.1 or later (latest stable 4.x recommended)

  1. 1. Stop the PowerDNS Authoritative service
  2. 2. Backup all configuration files, zone data, and the database (if using a backend like BIND, LMDB, or others)
  3. 3. Upgrade PowerDNS Authoritative to version 4.3.1 or later (recommended: latest stable 4.x release)
  4. 4. Verify the upgrade was successful by running: pdns --version
  5. 5. Review the new configuration to ensure GSS-TSIG settings are correct if still needed
  6. 6. Start the PowerDNS Authoritative service
  7. 7. Monitor logs for any errors or issues
Caveat Review release notes for any configuration or behavior changes between 4.3.0 and the target version; GSS-TSIG remains experimental so test thoroughly before production use

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

Fix this in Authoritative Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing6.0 h
  • Review / QA3.0 h
18.0 hours of engineering $3,120
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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-2020-24698 in production — separate from our analysis above.

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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