CVE catalog

CVE-2020-10995

pdns-recursor affected and fixed versions

PowerDNS Recursor from 4.1.0 up to and including 4.3.0 does not sufficiently defend against amplification attacks. An issue in the DNS protocol has been found that allow malicious parties to use recursive DNS services to attack third party authoritative name servers. The attack uses a crafted reply by an authoritative name server to amplify the resulting traffic between the recursive and other authoritative name servers. Both types of service can suffer degraded performance as an effect. This is triggered by random subdomains in the NSDNAME in NS records. PowerDNS Recursor 4.1.16, 4.2.2 and 4.3.1 contain a mitigation to limit the impact of this DNS protocol issue.

Severity: High · CVSS 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published: May 19, 2020, 12:00:00 AM UTC
Source: [NVD] · [CVE record]
EPSS: 4.48% · Oct 27, 2026

Projects and upstream resources

[pdns][Source-reported homepage]

Reported versions and fixes

Each observation applies to its named package, distribution, and release. Distribution backports can fix a vulnerability while retaining an older upstream version number.

Distribution / release	Package	Version	Status	Source
Debiantrixie-security	pdns-recursor	`5.2.13-0+deb13u1`	Fixed	[CVE-2020-10995]
Debiantrixie	pdns-recursor	`4.3.1-1`	FixedDistribution-reported fixed boundary	[CVE-2020-10995]
Debiantrixie	pdns-recursor	`5.2.13-0+deb13u1`	Fixed	[CVE-2020-10995]
Debiansid	pdns-recursor	`4.3.1-1`	FixedDistribution-reported fixed boundary	[CVE-2020-10995]
Debiansid	pdns-recursor	`5.4.9-1`	Fixed	[CVE-2020-10995]
Debianforky	pdns-recursor	`4.3.1-1`	FixedDistribution-reported fixed boundary	[CVE-2020-10995]
Debianforky	pdns-recursor	`5.4.8-1`	Fixed	[CVE-2020-10995]
Debianbookworm-security	pdns-recursor	`4.8.8-1+deb12u1`	Fixed	[CVE-2020-10995]
Debianbookworm	pdns-recursor	`4.3.1-1`	FixedDistribution-reported fixed boundary	[CVE-2020-10995]
Debianbookworm	pdns-recursor	`4.8.8-1+deb12u1`	Fixed	[CVE-2020-10995]

Showing 10 fix observations. All 15 observations, including unknown and conflicting reports, are available below.

Provider details and historical evidence

Distribution / release	Package	Version	Status	Source
Debianbookworm	pdns-recursor	`4.3.1-1`	FixedDistribution-reported fixed boundary	[CVE-2020-10995]
Debianbookworm	pdns-recursor	`4.8.8-1+deb12u1`	Fixed	[CVE-2020-10995]
Debianbookworm-security	pdns-recursor	`4.8.8-1+deb12u1`	Fixed	[CVE-2020-10995]
Debianforky	pdns-recursor	`4.3.1-1`	FixedDistribution-reported fixed boundary	[CVE-2020-10995]
Debianforky	pdns-recursor	`5.4.8-1`	Fixed	[CVE-2020-10995]
Debiansid	pdns-recursor	`4.3.1-1`	FixedDistribution-reported fixed boundary	[CVE-2020-10995]
Debiansid	pdns-recursor	`5.4.9-1`	Fixed	[CVE-2020-10995]
Debiantrixie	pdns-recursor	`4.3.1-1`	FixedDistribution-reported fixed boundary	[CVE-2020-10995]
Debiantrixie	pdns-recursor	`5.2.13-0+deb13u1`	Fixed	[CVE-2020-10995]
Debiantrixie-security	pdns-recursor	`5.2.13-0+deb13u1`	Fixed	[CVE-2020-10995]
Ubuntupro	pdns-recursor	`4.2.0-6`	UnknownSource applicability is not established	[UBUNTU-CVE-2020-10995]Sep 8, 2025, 4:46:03 PM UTC
Ubuntupro	pdns-recursor	`4.2.1-1`	UnknownSource applicability is not established	[UBUNTU-CVE-2020-10995]Sep 8, 2025, 4:46:03 PM UTC
Ubuntupro	pdns-recursor	`4.2.1-1build1`	UnknownSource applicability is not established	[UBUNTU-CVE-2020-10995]Sep 8, 2025, 4:46:03 PM UTC
Ubuntupro	pdns-recursor	`4.2.1-1build2`	UnknownSource applicability is not established	[UBUNTU-CVE-2020-10995]Sep 8, 2025, 4:46:03 PM UTC
Ubuntupro	pdns-recursor	`4.2.1-1ubuntu0.1~esm1`	UnknownSource applicability is not established	[UBUNTU-CVE-2020-10995]Sep 8, 2025, 4:46:03 PM UTC

Original provider fields

{
  "package_releases": [
    {
      "name": "pdns-recursor",
      "status": "fixed",
      "release": "sid",
      "version": "5.4.9-1"
    },
    {
      "name": "pdns-recursor",
      "status": "fixed",
      "release": "forky",
      "version": "5.4.8-1"
    },
    {
      "name": "pdns-recursor",
      "status": "fixed",
      "release": "trixie",
      "version": "5.2.13-0+deb13u1"
    },
    {
      "name": "pdns-recursor",
      "status": "fixed",
      "release": "trixie-security",
      "version": "5.2.13-0+deb13u1"
    },
    {
      "name": "pdns-recursor",
      "status": "fixed",
      "release": "bookworm",
      "version": "4.8.8-1+deb12u1"
    },
    {
      "name": "pdns-recursor",
      "status": "fixed",
      "release": "bookworm-security",
      "version": "4.8.8-1+deb12u1"
    }
  ],
  "fixed_versions": [
    {
      "bug": null,
      "name": "pdns-recursor",
      "type": "source",
      "origin": null,
      "release": "sid",
      "urgency": "not yet assigned",
      "fixed_version": "4.3.1-1"
    },
    {
      "bug": null,
      "name": "pdns-recursor",
      "type": "source",
      "origin": null,
      "release": "forky",
      "urgency": "not yet assigned",
      "fixed_version": "4.3.1-1"
    },
    {
      "bug": null,
      "name": "pdns-recursor",
      "type": "source",
      "origin": null,
      "release": "trixie",
      "urgency": "not yet assigned",
      "fixed_version": "4.3.1-1"
    },
    {
      "bug": null,
      "name": "pdns-recursor",
      "type": "source",
      "origin": null,
      "release": "bookworm",
      "urgency": "not yet assigned",
      "fixed_version": "4.3.1-1"
    }
  ],
  "distribution_packages": [
    {
      "name": "pdns-recursor",
      "distro": "ubuntu",
      "ranges": [
        {
          "type": "ECOSYSTEM",
          "events": [
            {
              "introduced": "0"
            }
          ]
        }
      ],
      "release": "pro",
      "versions": [
        "4.2.0-6",
        "4.2.1-1",
        "4.2.1-1build1",
        "4.2.1-1build2",
        "4.2.1-1ubuntu0.1~esm1"
      ],
      "ecosystem": "deb",
      "provider_url": "https://osv.dev/vulnerability/UBUNTU-CVE-2020-10995",
      "fixed_version": "",
      "provider_source": "pypi",
      "provider_record_id": "UBUNTU-CVE-2020-10995",
      "provider_updated_at": "2025-09-08T16:46:03Z",
      "applicability_unknown": true
    }
  ]
}

OpenFactory catalog packages

Matching against OpenFactory catalog package versions is in progress.

[Debian 12 (Bookworm)]

[pdns-recursor]Unknown
Details (4)
- 4.8.8-1+deb12u1 · amd64 · bookworm
  Fixed · Fixed: 4.3.1-1
  dsa · pdns-recursor · debian · bookworm; dsa · pdns-recursor · debian · 12
- 4.8.8-1+deb12u1 · arm64 · bookworm
  Fixed · Fixed: 4.3.1-1
  dsa · pdns-recursor · debian · bookworm; dsa · pdns-recursor · debian · 12
- 4.8.8-1+deb12u1 · amd64 · bookworm-security
  Fixed · Fixed: 4.3.1-1
  dsa · pdns-recursor · debian · bookworm; dsa · pdns-recursor · debian · 12
- 4.8.8-1+deb12u1 · arm64 · bookworm-security
  Fixed · Fixed: 4.3.1-1
  dsa · pdns-recursor · debian · bookworm; dsa · pdns-recursor · debian · 12

[Debian 13 (Trixie)]

[pdns-recursor]Unknown
Details (4)
- 5.2.11-0+deb13u1 · amd64 · trixie
  Fixed · Fixed: 4.3.1-1
  dsa · pdns-recursor · debian · 13
- 5.2.11-0+deb13u1 · arm64 · trixie
  Fixed · Fixed: 4.3.1-1
  dsa · pdns-recursor · debian · 13
- 5.2.13-0+deb13u1 · amd64 · trixie-security
  Fixed · Fixed: 4.3.1-1
  dsa · pdns-recursor · debian · 13
- 5.2.13-0+deb13u1 · arm64 · trixie-security
  Fixed · Fixed: 4.3.1-1
  dsa · pdns-recursor · debian · 13

Observed: Oct 23, 2026, 5:46:38 PM UTC

References

[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]