CVE-2021-36754 [High] | Memory Corruption in Authoritative Server

CVE-2021-36754 is rated High Risk (69.9/100): CVSS High severity, with high exploitation likelihood (EPSS 91.83%, 100th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +10.49% over the last day, indicating growing attacker interest. High exploitation likelihood—assess exposure and prioritize remediation.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-05-29	81.34%	91.83%	+10.49%
2	2026-03-19	84.52%	81.34%	-3.18%
3	2026-01-18	—	84.52%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-05-29

81.34%

91.83%

+10.49%

2026-03-19

84.52%

81.34%

-3.18%

2026-01-18

—

84.52%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
7.5	3.1	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	3.9	3.6	[email protected]
5.0	2.0	MEDIUM	`AV:N/AC:L/Au:N/C:N/I:N/A:P` Click to expand Access vector (AV:N) Can be exploited remotely over network reachability. Access complexity (AC:L) Exploitation conditions are straightforward and predictable. Authentication (AU:N) No authentication is required. Confidentiality impact (C:N) No confidentiality impact. Integrity impact (I:N) No integrity impact. Availability impact (A:P) Partial availability impact.	10.0	2.9	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

7.5

3.1

HIGH

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

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N): Doesn’t really leak secrets in a meaningful way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

3.9

3.6

[email protected]

5.0

2.0

MEDIUM

AV:N/AC:L/Au:N/C:N/I:N/A:P Click to expand

Access vector (AV:N): Can be exploited remotely over network reachability.
Access complexity (AC:L): Exploitation conditions are straightforward and predictable.
Authentication (AU:N): No authentication is required.
Confidentiality impact (C:N): No confidentiality impact.
Integrity impact (I:N): No integrity impact.
Availability impact (A:P): Partial availability impact.

10.0

2.9

[email protected]

OS Trackers for CVE-2021-36754

vendor	priority	summary	link
`alpine`	high	CVE-2021-36754: 1 source package rows (pdns); 7 state rows across 7 repos (3.17-community, 3.18-community, 3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community); fixed 7, open 0.	https://security.alpinelinux.org/vuln/CVE-2021-36754
`debian`	unimportant	CVE-2021-36754 unimportant priority: Debian including 1 source packages (pdns), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5.	https://security-tracker.debian.org/tracker/CVE-2021-36754
`suse`	high	CVE-2021-36754 severity important: SUSE including 12 source package names (pdns, pdns-4.5.1-1.5, …), 16 product×package rows across 4 product lines (HPE Helion OpenStack 8, SUSE OpenStack Cloud 8, SUSE OpenStack Cloud 9, openSUSE Tumbleweed): Fixed 10, Known Not Affected 6.	https://www.suse.com/security/cve/CVE-2021-36754/
`ubuntu`	low	CVE-2021-36754 low priority: Ubuntu including 1 source packages (pdns), 13 status rows across 13 suites (bionic, focal, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, trusty, upstream, xenial): not-affected 7, ignored 5, DNE 1.	https://ubuntu.com/security/CVE-2021-36754

Affected software / configurations for CVE-2021-36754

Vendor	Product	Version	Raw CPE
powerdns	authoritative_server	>= 4.5.0, < 4.5.1	cpe:2.3:a:powerdns:authoritative_server::::::::

References for CVE-2021-36754

URL	Tags
http://www.openwall.com/lists/oss-security/2021/07/26/2	Mailing List Third Party Advisory
https://doc.powerdns.com/authoritative/security-advisories/index.html	Vendor Advisory
https://doc.powerdns.com/authoritative/security-advisories/powerdns-advisory-2021-01.html	Vendor Advisory

URL

CVE-2021-36754

Exploit prediction scoring system (EPSS) score for CVE-2021-36754

Common vulnerability scoring system (CVSS) metrics for CVE-2021-36754

Weakness enumeration for CVE-2021-36754

OS Trackers for CVE-2021-36754

Affected software / configurations for CVE-2021-36754

References for CVE-2021-36754