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Powerdns CVE-2021-36754

HIGH
Buffer Overflow (CWE-119)
2021-07-30 cve@mitre.org
7.5
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Bounds checking, buffer size validation
MITRE ATT&CK

2 techniques across 2 tactics: Execution, Privilege Escalation

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Impact

CVSS score of 7.5 (HIGH). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required.

Exploit ScenarioDerived

A remote attacker could corrupt memory to execute arbitrary code or crash the application by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability.

This Week Schedule remediation this week. Why: HIGH severity + EPSS > 10%.
No patch listed yet 64.9% exploitation probability (EPSS)

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AnalysisAI

PowerDNS Authoritative Server 4.5.0 before 4.5.1 allows anybody to crash the process by sending a specific query (QTYPE 65535) that causes an out-of-bounds exception. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Use memory-safe languages or bounds-checking. Enable ASLR, DEP/NX, stack canaries. Use safe string functions.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as Buffer Overflow (CWE-119), which allows attackers to corrupt memory to execute arbitrary code or crash the application. PowerDNS Authoritative Server 4.5.0 before 4.5.1 allows anybody to crash the process by sending a specific query (QTYPE 65535) that causes an out-of-bounds exception. Affected products include: Powerdns Authoritative Server. Version information: before 4.5.1.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 7.5 HIGH
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

DescriptionNVD

PowerDNS Authoritative Server 4.5.0 before 4.5.1 allows anybody to crash the process by sending a specific query (QTYPE 65535) that causes an out-of-bounds exception.

Threat Intelligence Overview

EPSS Score
64.9%
Top 1% exploitable
Exploit
POC
Public exploit code exists
Data Quality
2 sources
Confidence: Low

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC Yes
EPSS 64.9%
Patch available No
Active threat Yes
Deciding rule
HIGH severity + EPSS > 10%
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
Poc
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact· derived
Medium

Priority Score

123
Low Medium High Critical
KEV: 0
EPSS: +65
CVSS: +38
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.

Affected Products (CPE)NVD

cpe:2.3:a:powerdns:authoritative_server:*:*:*:*:*:*:*:*
CVE-2016-5427 HIGH
7.5 Sep 21

PowerDNS (aka pdns) Authoritative Server before 3.4.10 does not properly handle a . Rated high severity (CVSS 7.5), this

CVE-2016-5426 HIGH
7.5 Sep 21

PowerDNS (aka pdns) Authoritative Server before 3.4.10 allows remote attackers to cause a denial of service (backend CPU

CVE-2019-3871 HIGH POC
8.8 Mar 21

A vulnerability was found in PowerDNS Authoritative Server before 4.0.7 and before 4.1.7. Rated high severity (CVSS 8.8)

CVE-2012-1193 MEDIUM POC
6.4 Feb 17

The resolver in PowerDNS Recursor (aka pdns_recursor) 3.3 overwrites cached server names and TTL values in NS records du

CVE-2020-24698 CRITICAL
9.8 Oct 02

An issue was discovered in PowerDNS Authoritative through 4.3.0 when --enable-experimental-gss-tsig is used. Rated criti

CVE-2019-3807 CRITICAL
9.8 Jan 29

An issue has been found in PowerDNS Recursor versions 4.1.x before 4.1.9 where records in the answer section of response

CVE-2017-7557 HIGH
8.8 Aug 22

dnsdist version 1.1.0 is vulnerable to a flaw in authentication mechanism for REST API potentially allowing CSRF attack.

CVE-2020-10030 HIGH
8.8 May 19

An issue has been found in PowerDNS Recursor 4.1.0 up to and including 4.3.0. Rated high severity (CVSS 8.8), this vulne

CVE-2026-42000 HIGH
8.6 May 21

Denial of service in PowerDNS Authoritative DNS server (versions 4.9.0-4.9.14 and 5.0.0-5.0.4) arises from insufficient

CVE-2026-24028 HIGH
8.2 Mar 31

Out-of-bounds read in PowerDNS dnsdist allows unauthenticated remote attackers to trigger denial of service or potential

CVE-2025-59023 HIGH
8.2 Feb 09

Crafted delegations or IP fragments can poison cached delegations in Recursor. [CVSS 8.2 HIGH]

CVE-2020-24696 HIGH
8.1 Oct 02

An issue was discovered in PowerDNS Authoritative through 4.3.0 when --enable-experimental-gss-tsig is used. Rated high

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