SB20260422205 - Multiple vulnerabilities in PowerDNS Recursor
Published: April 22, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 9 vulnerabilities.
1) Allocation of Resources Without Limits or Throttling (CVE-ID: CVE-2026-33256)
CWE-ID: CWE-770 - Allocation of Resources Without Limits or Throttling
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to uncontrolled resource allocation in internal web server when handling crafted HTTP requests. A remote attacker can send a crafted HTTP request to cause a denial of service.
Note, the internal web server is disabled by default.
2) Allocation of Resources Without Limits or Throttling (CVE-ID: CVE-2026-33257)
CWE-ID: CWE-770 - Allocation of Resources Without Limits or Throttling
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to uncontrolled resource allocation in internal web server when handling crafted HTTP requests. A remote attacker can send a crafted HTTP request to cause a denial of service.
Note, the internal web server is disabled by default.
3) Allocation of Resources Without Limits or Throttling (CVE-ID: CVE-2026-33258)
CWE-ID: CWE-770 - Allocation of Resources Without Limits or Throttling
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to uncontrolled resource allocation in negative and aggressive NSEC(3) caches when processing crafted zones and DNS responses. A remote attacker can publish and query a crafted zone to cause a denial of service.
4) Use-after-free (CVE-ID: CVE-2026-33259)
CWE-ID: CWE-416 - Use After Free
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to use-after-free in RPZ data handling when processing many concurrent transfers of the same RPZ. A remote privileged user can trigger many concurrent transfers of the same RPZ to cause a denial of service.
Exploitation normally requires a malfunctioning RPZ provider.
5) Allocation of Resources Without Limits or Throttling (CVE-ID: CVE-2026-33260)
CWE-ID: CWE-770 - Allocation of Resources Without Limits or Throttling
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to uncontrolled resource allocation in internal web server when handling crafted HTTP requests. A remote attacker can send a crafted HTTP request to cause a denial of service.
Note. the internal web server is disabled by default.
6) Missing support for integrity check (CVE-ID: CVE-2026-33261)
CWE-ID: CWE-353 - Missing Support for Integrity Check
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to internal inconsistency in aggressive NSEC(3) cache when a zone transitions from NSEC to NSEC3. A remote attacker can trigger a zone transition from NSEC to NSEC3 to cause a denial of service.
7) NULL pointer dereference (CVE-ID: CVE-2026-33262)
CWE-ID: CWE-476 - NULL Pointer Dereference
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to null pointer dereference in cookie reply handling when processing crafted DNS responses. A remote attacker can send a crafted DNS response to cause a denial of service.
Note, cookies are disabled by default.
8) NULL pointer dereference (CVE-ID: CVE-2026-33601)
CWE-ID: CWE-476 - NULL Pointer Dereference
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to null pointer dereference in zoneToCache ZONEMD record handling when processing a crafted zonemd record from a malicious authoritative server. A remote privileged user can send a crafted zonemd record to cause a denial of service.
Exploitation requires the zoneToCache function to be configured.
9) NULL pointer dereference (CVE-ID: CVE-2026-33600)
CWE-ID: CWE-476 - NULL Pointer Dereference
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to null pointer dereference in RPZ transfer handling when processing a crafted RPZ from a malicious authoritative server. A remote privileged user can send a crafted RPZ to cause a denial of service.
Remediation
Install update from vendor's website.