CVE-2026-123583
LowCVSS 3.7Exploitation Probability (EPSS)
Low risk2th percentile - higher than 2% of all known CVEs
Summary
The recursive resolver in Hickory DNS hickory-recursor 0.25.0 through 0.25.2 and hickory-resolver 0.26.0 before 0.26.2 does not apply out-of-bailiwick filtering to negative responses. Attackers able to supply crafted negative responses can include out-of-bailiwick records to facilitate cache poisoning and more easily exploit other DNSSEC verification flaws.
Risk Assessment
An attacker can poison the DNS cache and exploit other DNSSEC flaws, redirecting traffic to malicious servers.
Recommendation
Upgrade hickory-recursor to version 0.25.2 or later and hickory-resolver to version 0.26.2 or later.
Other vulnerabilities in Hickory DNS
See all- CVE-2026-123604High
Hickory DNS hickory-resolver 0.26.0-beta.1 before 0.26.2 contains an unbounded retry loop in NameServerPool::try_send that re-queues truncated (TC) responses without checking the answering transport or counting iterations. A malicious authoritative server returning TC=1 on every transport keeps the resolver spinning on a persistent TCP connection until the 5-second request deadline expires, causing resource exhaustion.
- CVE-2026-123603Medium
hickory-proto and hickory-resolver 0.26.0 before 0.26.2, hickory-server 0.25.0-alpha.1 before 0.26.2, and hickory-recursor 0.25.0-alpha.3 through 0.26.0-alpha.1 fail to canonicalize IPv4-mapped IPv6 addresses when checking deny_answers, deny_server, or AccessControlSet rules. Attackers can use IPv4-mapped addresses to evade answer filtering, trigger queries to denied nameservers, or reach hickory-server library deployments on dual-stack IPv6 sockets from denied clients.
- CVE-2026-123602Medium
The Hickory DNS recursor in all versions of hickory-recursor and in hickory-resolver 0.26.0-beta.1 before 0.26.2 (recursor feature) is vulnerable to ghost domain names attacks because it reuses child-side apex NS RRsets cached from zone NS queries for iterative resolution. By repeatedly querying a zone's NS records, an attacker keeps the stale RRset cached indefinitely, letting name servers whose delegation the parent revoked keep answering for the zone.
- CVE-2026-123601Medium
Hickory DNS hickory-proto 0.25.0 through 0.26.0-alpha.1 and hickory-net 0.26.0-beta.1 before 0.26.2 invert the relational operators in the wrap-around branch of find_covering_record() in nsec3.rs, so the last NSEC3 record in a zone's hash ring covers every hash except its owner. Attackers able to inject DNS responses can replay that NSEC3 record and its RRSIG to forge DNSSEC-validated negative responses denying legitimate names.
- CVE-2026-123600Medium
Hickory DNS hickory-proto 0.25.0-alpha.3 through 0.25.2 and hickory-net 0.26.0-alpha.1 before 0.26.2 contain a DNSSEC validation flaw in DnssecDnsHandle that accepts NSEC3-signed NODATA responses for zone-apex queries as secure without an NSEC3 record matching the hashed QNAME. On-path attackers or malicious authoritative servers can replay a validly signed non-apex NSEC3 with the zone's signed SOA to serve an authenticated (AD=1) denial of any apex RRtype for the negative-cache TTL.
- CVE-2026-123599Low
Hickory DNS hickory-proto before 0.26.0-beta.1 and hickory-net before 0.26.2 contain a DNSSEC validation bypass because verify_rrsets() ignores DNS class when partitioning RRsets, so non-IN records skip signature verification yet are marked secure when the IN records verify. Attackers able to supply DNS responses can include forged CH or HS class records, including DS records, to authenticate any DNSKEY and forge child zone responses.
- CVE-2026-123598Low
The validating recursor in Hickory DNS hickory-recursor 0.25.0 through 0.26.0-alpha.1, hickory-resolver 0.26.0-alpha.1 before 0.26.2, and hickory-net 0.26.0-beta.1 before 0.26.2 caches DNSSEC-bogus answers using the untrusted, attacker-supplied record TTL (capped at 24 hours) instead of a short validation-failure TTL. A remote attacker who spoofs a single authoritative response with an invalid signature and a long TTL can keep the bogus result cached for up to 24 hours.
- CVE-2026-123597Low
Hickory DNS hickory-proto 0.25.0-alpha.1 through 0.26.0-alpha.1 and hickory-net before 0.26.2 contain a logic bug in DnssecDnsHandle's DS-fetch path that caches transient DS lookup errors as Bogus DNSSEC validation verdicts. An attacker who induces a SERVFAIL, REFUSED, or timeout response to a child-zone DS sub-query causes the validator to return SERVFAIL for all names under that zone until the cache entry's TTL expires.
- CVE-2026-123596High
Hickory DNS hickory-proto through 0.26.0-alpha.1 and hickory-net 0.26.0-beta.1 before 0.26.2 contain a DNSSEC validation flaw in the validating recursor's NSEC handler that accepts parent-side ancestor-delegation NSEC records as proof of nonexistence for names below the zone cut. An on-path attacker, rogue parent nameserver, or attacker winning a port and TXID race can deliver one forged NXDOMAIN response built from genuinely signed parent NSEC records, causing authenticated denial of existing child-zone names cached for the negative TTL.
- CVE-2026-123595High
Hickory DNS hickory-proto 0.25 through 0.26.0-alpha.1 and hickory-net 0.26.0-beta.1 before 0.26.2 contain a DNSSEC validation flaw in the validating recursor's NSEC3 handler, which matches the closest encloser by hash alone without checking the type bitmap and so accepts parent-side ancestor-delegation NSEC3 records as proof of nonexistence. An attacker who delivers one response built from genuinely signed parent NSEC3 records can cause NXDOMAIN or NODATA to be cached with AD=1, denying resolution of existing names at and below the zone cut.
Original NVD description (English source)
The recursive resolver in Hickory DNS hickory-recursor 0.25.0 through 0.25.2 and hickory-resolver 0.26.0 before 0.26.2 does not apply out-of-bailiwick filtering to negative responses. Attackers able to supply crafted negative responses can include out-of-bailiwick records to facilitate cache poisoning and more easily exploit other DNSSEC verification flaws.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS