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CVE-2026-123604— Hickory DNS 0.26.0-beta.1 before 0.26.2 Resource Exhaustion DoS via NameServerPool::try_send TC-Retry Loop

Quick assessment

Affected
hickory-dns hickory-dns
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Hickory DNS 的 hickory-resolver 在 0.26.0-beta.1 至 0.26.2 之前的版本中存在一个无界重试循环漏洞，位于 函数中。该函数在重新排队截断（TC）响应时，未检查响应所对应的传输协议，也未对迭代次数进行限制。若恶意权威服务器在所有传输协议上均返回 TC=1（截断标志位为 1），将导致解析器在持久的 TCP 连接上持续循环，直至 5 秒的请求超时期限耗尽，从而引发资源耗尽攻击。

CVSS 7.5 · High
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I. Basic Information for CVE-2026-123604

Vulnerability Information
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Vulnerability Title
Hickory DNS 0.26.0-beta.1 before 0.26.2 Resource Exhaustion DoS via NameServerPool::try_send TC-Retry Loop
Source: CVE Program / CVE List V5
Vulnerability Description
Hickory DNS hickory-resolver 0.26.0-beta.1 before 0.26.2 contains an unbounded retry loop in NameServerPool::try_send, which 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
不可达退出条件的循环(无限循环)
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
hickory-dns hickory-dns 0.26.0-beta.1 ~ 0.26.2 -

II. Public POCs for CVE-2026-123604

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III. Intelligence Information for CVE-2026-123604

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Other References for CVE-2026-123604 (2)

Same Patch Batch · hickory-dns · 2026-11-08 · 39 CVEs total

CVE-2026-123595 8.8 HIGH Hickory DNS through 0.26.0-alpha.1 DNSSEC Validation Bypass via Ancestor-Delegation NSEC3
CVE-2026-123596 8.8 HIGH Hickory DNS through 0.26.0-alpha.1 DNSSEC Validation Bypass via Ancestor-Delegation NSEC
CVE-2026-123605 8.8 HIGH Hickory DNS through 0.25.0-alpha.3 DNSSEC Validation Bypass via RRSIG Signer's Name
CVE-2026-123570 7.5 HIGH Hickory DNS from 0.18 before 0.26.2 Memory Amplification DoS via RR Counts
CVE-2026-123571 7.5 HIGH Hickory DNS from 0.26.0 before 0.26.2 Panic via TSIG RDATA Decoding
CVE-2026-123580 7.5 HIGH Hickory-DNS 0.26.0-beta.1 before 0.26.2 DNSSEC Nonexistence Proof Forgery via NSEC3
CVE-2026-123588 7.5 HIGH Hickory DNS Recursive Resolver Denial of Service via Cached Empty Connection Pool
CVE-2026-123572 7.5 HIGH Hickory-dns 0.20.1 before 0.26.2 Panic DoS via SVCB/HTTPS Zone Parser
CVE-2026-123574 7.5 HIGH Hickory DNS 0.24.0 before 0.26.2 Denial of Service via Zone File Parser
CVE-2026-123575 7.5 HIGH Hickory DNS before 0.26.2 DoH Memory Exhaustion via Incomplete Request Bodies
CVE-2026-123577 7.5 HIGH Hickory DNS 0.24.0 before 0.26.2 DoH Unbounded Request Body Denial of Service
CVE-2026-123576 7.5 HIGH Hickory DNS 0.24.0 through 0.26.1 Memory Exhaustion via DNS-over-QUIC Requests
CVE-2026-123573 7.5 HIGH hickory-dns from 0.20.1 before 0.26.2 Panic in SVCB/HTTPS Zone File Parser
CVE-2026-123607 7.5 HIGH Hickory DNS NSEC3 Closest-Encloser Proof Unbounded Loop Denial of Service
CVE-2026-123606 7.5 HIGH Hickory-DNS Recursor 0.25.0-alpha.3 through 0.25.2 Glueless-NS Referral Amplification
CVE-2026-123608 7.5 HIGH Hickory DNS hickory-proto 0.3.1 before 0.26.1 CPU Exhaustion via BinEncoder Name Compressi
CVE-2026-123586 7.5 HIGH Hickory DNS 0.25.0-alpha.3 through 0.25.2 Query Amplification via Cyclic Referrals
CVE-2026-123587 6.8 MEDIUM Hickory-DNS 0.26.0 before 0.26.2 DNSSEC Nonexistence Forgery via Wraparound NSEC
CVE-2026-123601 6.5 MEDIUM Hickory DNS 0.26.0-beta.1 before 0.26.2 NSEC3 Proof of Nonexistence Forgery
CVE-2026-123603 6.5 MEDIUM Hickory DNS Missing IPv4-Mapped IPv6 Canonicalization Access Control Bypass

Showing top 20 of 39 CVEs. View all on vendor page → →

IV. Related Vulnerabilities

Same product: hickory-dns
Same vendor: hickory-dns
Same weakness: CWE-835