Buffer overflow in PowerDNS Recursor before 3.1.7.2 allows remote attackers to cause a denial of service (daemon crash) or possibly execute arbitrary code via crafted packets.

pdns specific as packaged in Debian in version before 3.3.1-1 creates a too privileged MySQL user. It was discovered that the maintainer scripts of pdns-backend-mysql grant too wide database permissions for the pdns user. Other backends are not affected.

An attacker can send a notify request that causes a new secondary domain to be added to the bind backend, but causes said backend to update its configuration to an invalid one, leading to the backend no longer able to run on the next restart, requiring manual operation to fix it.

An issue has been found in PowerDNS Recursor versions 4.1.x before 4.1.9 where records in the answer section of responses received from authoritative servers with the AA flag not set were not properly validated, allowing an attacker to bypass DNSSEC validation.

An issue was discovered in PowerDNS Authoritative through 4.3.0 when --enable-experimental-gss-tsig is used. A remote, unauthenticated attacker might be able to cause a double-free, leading to a crash or possibly arbitrary code execution. by sending crafted queries with a GSS-TSIG signature.

Last updated 14 January 2025

A cached crafted response can cause an out-of-bounds read if custom Lua code calls getDomainListByAddress() or getAddressListByDomain() on a packet cache.

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

A vulnerability was found in PowerDNS Authoritative Server before 4.0.7 and before 4.1.7. An insufficient validation of data coming from the user when building a HTTP request from a DNS query in the HTTP Connector of the Remote backend, allowing a remote user to cause a denial of service by making the server connect to an invalid endpoint, or possibly information disclosure by making the server connect to an internal endpoint and somehow extracting meaningful information about the response

An issue has been found in PowerDNS Recursor 4.1.0 up to and including 4.3.0. It allows an attacker (with enough privileges to change the system's hostname) to cause disclosure of uninitialized memory content via a stack-based out-of-bounds read. It only occurs on systems where gethostname() does not have '\0' termination of the returned string if the hostname is larger than the supplied buffer. (Linux systems are not affected because the buffer is always large enough. OpenBSD systems are not affected because the returned hostname always has '\0' termination.) Under some conditions, this issue can lead to the writing of one '\0' byte out-of-bounds on the stack, causing a denial of service or possibly arbitrary code execution.

Insufficient Validation of Names During AXFR

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

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.

A rogue backend can send a crafted UDP response with a query ID off by one related to the maximum configured value, triggering an out-of-bounds write leading to a denial of service.

A rogue backend can send a crafted SVCB response to a Discovery of Designated Resolvers request, when requested via either the autoUpgrade (Lua) option to newServer or autoupgrade (YAML) settings. DDR upgrade is not enabled by default.

An issue has been found in PowerDNS Recursor versions after 4.1.3 before 4.1.9 where Lua hooks are not properly applied to queries received over TCP in some specific combination of settings, possibly bypassing security policies enforced using Lua.

An issue was discovered in PowerDNS Authoritative through 4.3.0 when --enable-experimental-gss-tsig is used. A remote, unauthenticated attacker can trigger a race condition leading to a crash, or possibly arbitrary code execution, by sending crafted queries with a GSS-TSIG signature.

The label decompression functionality in PowerDNS Recursor 3.5.x, 3.6.x before 3.6.3, and 3.7.x before 3.7.2 and Authoritative (Auth) Server 3.2.x, 3.3.x before 3.3.2, and 3.4.x before 3.4.4 allows remote attackers to cause a denial of service (CPU consumption or crash) via a request with a name that refers to itself.

The label decompression functionality in PowerDNS Recursor before 3.6.4 and 3.7.x before 3.7.3 and Authoritative (Auth) Server before 3.3.3 and 3.4.x before 3.4.5 allows remote attackers to cause a denial of service (CPU consumption or crash) via a request with a long name that refers to itself. NOTE: this vulnerability exists because of an incomplete fix for CVE-2015-1868.

An issue has been found in PowerDNS before 3.4.11 and 4.0.2, and PowerDNS recursor before 3.7.4 and 4.0.4, allowing a remote, unauthenticated attacker to cause an abnormal CPU usage load on the PowerDNS server by sending crafted DNS queries, which might result in a partial denial of service if the system becomes overloaded. This issue is based on the fact that the PowerDNS server parses all records present in a query regardless of whether they are needed or even legitimate. A specially crafted query containing a large number of records can be used to take advantage of that behaviour.

Certain DNSSEC aspects of the DNS protocol (in RFC 4033, 4034, 4035, 6840, and related RFCs) allow remote attackers to cause a denial of service (CPU consumption) via one or more DNSSEC responses, aka the "KeyTrap" issue. One of the concerns is that, when there is a zone with many DNSKEY and RRSIG records, the protocol specification implies that an algorithm must evaluate all combinations of DNSKEY and RRSIG records.

ISC BIND is vulnerable to a denial of service, caused by an error when preparing an NSEC3 closest encloser proof. By flooding the target resolver with queries, a remote attacker could exploit this vulnerability to cause CPU exhaustion on a DNSSEC-validating resolver.

When incoming DNS over HTTPS support is enabled using the nghttp2 provider, and queries are routed to a tcp-only or DNS over TLS backend, an attacker can trigger an assertion failure in DNSdist by sending a request for a zone transfer (AXFR or IXFR) over DNS over HTTPS, causing the process to stop and thus leading to a Denial of Service. DNS over HTTPS is not enabled by default, and backends are using plain DNS (Do53) by default.

An attacker can publish a zone containing specific Resource Record Sets. Processing and caching results for these sets can lead to an illegal memory accesses and crash of the Recursor, causing a denial of service.

The remedy is: upgrade to the patched 5.2.1 version.

We would like to thank Volodymyr Ilyin for bringing this issue to our attention.

When DNSdist is configured to provide DoH via the nghttp2 provider, an attacker can cause a denial of service by crafting a DoH exchange that triggers an illegal memory access (double-free) and crash of DNSdist, causing a denial of service.

The remedy is: upgrade to the patched 1.9.9 version.

A workaround is to temporarily switch to the h2o provider until DNSdist has been upgraded to a fixed version.

We would like to thank Charles Howes for bringing this issue to our attention.

In some circumstances, when DNSdist is configured to allow an unlimited number of queries on a single, incoming TCP connection from a client, an attacker can cause a denial of service by crafting a TCP exchange that triggers an exhaustion of the stack and a crash of DNSdist, causing a denial of service.

The remedy is: upgrade to the patched 1.9.10 version.

A workaround is to restrict the maximum number of queries on incoming TCP connections to a safe value, like 50, via the setMaxTCPQueriesPerConnection setting.

We would like to thank Renaud Allard for bringing this issue to our attention.

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

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 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 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.