DNSdist DNS Processing Vulnerabilities

Out-of-bounds read in PowerDNS dnsdist allows unauthenticated remote attackers to trigger denial of service or potential information disclosure by sending a crafted DNS response packet when custom Lua code uses the newDNSPacketOverlay function to parse packets. CVSS 5.3 indicates moderate severity with network-accessible attack surface and no privilege or user interaction required.

Memory exhaustion in DNSdist allows remote, unauthenticated attackers to trigger denial of service by crafting malicious DNS over QUIC or DNS over HTTP/3 payloads that force excessive memory allocation. The attack causes the QUIC connection to close abnormally, and in systems with limited memory reserves, can force out-of-memory conditions that terminate the DNSdist process entirely.

DNSdist fails to validate packet size bounds when rewriting DNS questions or responses via Lua methods (DNSQuestion:changeName, DNSResponse:changeName), allowing unauthenticated remote attackers to craft DNS responses that trigger out-of-bounds writes and exceed the 65535-byte DNS packet size limit, resulting in denial of service via crash. CVSS 5.9 (high availability impact); no public exploit code identified at time of analysis.

DNSdist instances using custom Lua code can be crashed via denial of service when the DNSQuestion:getEDNSOptions method accesses a modified DNS packet, triggering a use-after-free condition. This affects DNSdist across all versions and requires network access to send crafted DNS queries, but the attack demands specific Lua code patterns and high attack complexity; no public exploit or active exploitation has been confirmed, and the real-world impact is limited to environments where custom Lua DNS query handlers reference EDNS options.

PowerDNS dnsdist allows unauthenticated DNS over HTTPS (DoH) queries to bypass access control lists when the early_acl_drop option is disabled on nghttp2 frontends, exposing the DNS resolver to unauthorized query submission and potential information disclosure. Affected versions include dnsdist across multiple releases where this configuration weakness exists; the vulnerability has a CVSS score of 6.5 and exposes both confidentiality and integrity concerns despite not affecting availability.

HTML injection in DNSdist internal web dashboard allows remote unauthenticated attackers to inject malicious content via crafted DNS queries when domain-based dynamic rules are enabled, requiring user interaction to exploit. This affects all DNSdist versions with vulnerable rule functionality and carries low integrity impact with no confidentiality or availability consequences.

Cross-Origin Resource Sharing (CORS) misconfiguration in PowerDNS dnsdist's internal webserver allows remote attackers to extract sensitive configuration information from the dashboard through a social engineering attack targeting authenticated administrators. An attacker can trick an admin into visiting a malicious website, which then leverages the misconfigured CORS policy to read dashboard API responses containing running configuration details. The vulnerability requires the internal webserver to be enabled (disabled by default) and user interaction, resulting in limited confidentiality impact with no integrity or availability risk.