PowerDNS vulnerabilities and threats

CVE-2026-33257 is a medium severity vulnerability in PowerDNS Authoritative versions 4.9.0 and 5.0.0. It allows an attacker to send a web request that triggers unlimited memory allocation in the internal web server, potentially causing a denial of service. The internal web server is disabled by default, which reduces the attack surface. There is no official patch or remediation level currently provided by the vendor. No known exploits are reported in the wild at this time.

CVE-2026-33256 is a medium severity vulnerability in PowerDNS Recursor versions 5.2.0, 5.3.0, and 5.4.0. It involves allocation of resources without limits or throttling in the internal web server, which is disabled by default. An attacker can send a web request that triggers unlimited memory allocation, potentially causing a denial of service. No official patch or remediation guidance is currently available.

CVE-2026-33601 is a medium severity vulnerability in PowerDNS Recursor versions 5.2.0, 5.3.0, and 5.4.0. It involves a NULL pointer dereference triggered when the zoneToCache function processes a malicious authoritative server's zone data without proper consistency checks. This flaw can cause a denial of service by crashing the service. There is no confirmed patch or official remediation available at this time, and no known exploits have been reported in the wild.

CVE-2026-33600 is a medium severity vulnerability in PowerDNS Recursor versions 5.2.0, 5.3.0, and 5.4.0. It involves a null pointer dereference triggered by a malicious authoritative server sending a crafted RPZ (Response Policy Zone) that lacks a necessary consistency check. This flaw can cause the PowerDNS Recursor to crash, resulting in a denial of service condition. There is no indication of confidentiality or integrity impact, and no known exploits are reported in the wild.

An attacker might be able to trigger a use-after-free by sending crafted DNS queries to a DNSdist using the DNSQuestion:getEDNSOptions method in custom Lua code. In some cases DNSQuestion:getEDNSOptions might refer to a version of the DNS packet that has been modified, thus triggering a use-after-free and potentially a crash resulting in denial of service.

An attacker might be able to trigger an out-of-bounds write by sending crafted DNS responses to a DNSdist using the DNSQuestion:changeName or DNSResponse:changeName methods in custom Lua code. In some cases the rewritten packet might become larger than the initial response and even exceed 65535 bytes, potentially leading to a crash resulting in denial of service.

An attacker might be able to trick DNSdist into allocating too much memory while processing DNS over QUIC or DNS over HTTP/3 payloads, resulting in a denial of service. In setups with a large quantity of memory available this usually results in an exception and the QUIC connection is properly closed, but in some cases the system might enter an out-of-memory state instead and terminate the process.

When the early_acl_drop (earlyACLDrop in Lua) option is disabled (default is enabled) on a DNS over HTTPs frontend using the nghttp2 provider, the ACL check is skipped, allowing all clients to send DoH queries regardless of the configured ACL.

An attacker might be able to trigger an out-of-bounds read by sending a crafted DNS response packet, when custom Lua code uses newDNSPacketOverlay to parse DNS packets. The out-of-bounds read might trigger a crash, leading to a denial of service, or access unrelated memory, leading to potential information disclosure.

When the internal webserver is enabled (default is disabled), an attacker might be able to trick an administrator logged to the dashboard into visiting a malicious website and extract information about the running configuration from the dashboard. The root cause of the issue is a misconfiguration of the Cross-Origin Resource Sharing (CORS) policy.

An attacker might be able to inject HTML content into the internal web dashboard by sending crafted DNS queries to a DNSdist instance where domain-based dynamic rules have been enabled via either DynBlockRulesGroup:setSuffixMatchRule or DynBlockRulesGroup:setSuffixMatchRuleFFI.

Crafted delegations or IP fragments can poison cached delegations in Recursor.

Crafted delegations or IP fragments can poison cached delegations in Recursor.

Crafted zones can lead to increased incoming network traffic.

Crafted zones can lead to increased resource usage and crafted CNAME chains can lead to cache poisoning in Recursor.

An attacker can trigger an assertion failure by requesting crafted DNS records, waiting for them to be inserted into the records cache, then send a query with qtype set to ANY.

An attacker can trigger the removal of cached records by sending a NOTIFY query over TCP.

In some circumstances, when DNSdist is configured to use the nghttp2 library to process incoming DNS over HTTPS queries, an attacker might be able to cause a denial of service by crafting a DoH exchange that triggers an unbounded I/O read loop, causing an unexpected consumption of CPU resources.

An attacker spoofing answers to ECS enabled requests sent out by the Recursor has a chance of success higher than non-ECS enabled queries. The updated version include various mitigations against spoofing attempts of ECS enabled queries by chaining ECS enabled requests and enforcing stricter validation of the received answers. The most strict mitigation done when the new setting outgoing.edns_subnet_harden (old style name edns-subnet-harden) is enabled.