CVE-2026-123604

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.

Overview

State: PUBLISHED
Assigner (CNA): VulnCheck
CVSS severity: HIGH
CVSS score: 8.7 / 10
CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Effective score: 8.7 / 10 HIGH source: CNA overview
CWE(s): CWE-835
Reserved: 2026-11-06
Published: 2026-11-08 01:38 UTC
Last updated: 2026-11-08 01:38 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/123xxx/CVE-2026-123604.json
Linked Threat: CVE-2026-123604 — Hickory DNS 0.26.0-beta.1 before 0.26.2 Resource Exhaustion DoS via NameServerPool::try_send TC-Retry Loop

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID: EUVD-2026-119363

EUVD enrichment is queued; refresh the page in a few seconds.

Affected products (1)

Vendor	Product	Versions	Platforms
hickory-dns	hickory-dns	`0.26.0-beta.1` (affected), `0.26.2` (unaffected)	—

Vendor references (2)

References embedded in the original CVE record by the assigning CNA.

GitHub Security Advisory (GHSA-6w6g-hm98-mhgm) vendor-advisory
VulnCheck Advisory: Hickory DNS 0.26.0-beta.1 before 0.26.2 Resource Exhaustion DoS via NameServerPool::try_send TC-Retry Loop third-party-advisory

MITRE references (2) cveawg.mitre.org

Pulled from MITRE's CVE Services API by the 🛰 Backfill from MITRE button.

GitHub Security Advisory (GHSA-6w6g-hm98-mhgm) vendor-advisory
VulnCheck Advisory: Hickory DNS 0.26.0-beta.1 before 0.26.2 Resource Exhaustion DoS via NameServerPool::try_send TC-Retry Loop third-party-advisory

Web references (0)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

No web references attached yet.

Remediations (10)

Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.

CISA Requires Federal Agencies to Patch Critical Vulnerabilities Within ...

web:cybersecuritynews.com

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has issued Binding Operational Directive (BOD) 26-04, titled "Prioritizing Security Updates Based on Risk," compelling all Federal Civilian Executive Branch (FCEB) agencies to remediate the most dangerous known exploited vulnerabilities within just three calendar days.

2026-11-08 10:22 UTC
CVE Vulnerabilities 2026: Critical Flaws & Fixes Hub

web:cyberupdates365.com

Track critical CVE vulnerabilities 2026 with verified enterprise patch guides. Fix zero-days across VMware, WordPress, Windows, and cloud infrastructure.

2026-11-08 10:22 UTC
Security Update Guide - Microsoft

web:msrc.microsoft.com

The Microsoft Security Response Center (MSRC) investigates all reports of security vulnerabilities affecting Microsoft products and services, and provides the information here as part of the ongoing effort to help you manage security risks and help keep your systems protected.

2026-11-08 10:22 UTC
Microsoft Patch Tracker (November 2026): Exploit-Ranked | Senserva

web:senserva.com

Every Microsoft security patch (KB) and the CVEs it fixes, with severity, CVSS, and CISA KEV status. Cross-linked to the CVE reference.

2026-11-08 10:22 UTC
ArcGIS Server Security 2026 Update 4 Patch - Esri Support

web:support.esri.com

The issues resolved by these patches are listed in the Issues addressed with this patch section below. As part of the patch installation, the ArcGIS Server service is stopped and restarted. The restart may take several minutes depending on the number of services published on the ArcGIS Server site. This patch can be uninstalled as outlined in the Uninstalling this patch on Windows and ...

2026-11-08 10:22 UTC
What Is CVE Remediation in 2026? - aikido.dev

web:www.aikido.dev

CVE remediation is fixing known flaws in the software you run. Why upgrading often fails, what remediation actually involves, and how backporting fixes it.

2026-11-08 10:22 UTC
Patch Smarter, Not Harder - CISA

web:www.cisa.gov

The median time for full resolution rose to 43 days. Defenders need greater clarity and speed to patch systems in today's threat landscape. We must flip the script on patching prioritization: patch smarter, not harder.

2026-11-08 10:22 UTC
The 8 Best Automated Vulnerability Remediation Tools in 2026

web:www.openhands.dev

Compare 8 automated vulnerability remediation tools for 2026 on fixes, prioritization, integrations, and deployment control.

2026-11-08 10:22 UTC
Oracle Critical Patch Update Advisory - July 2026

web:www.oracle.com

This Critical Patch Update contains 1448 new security patches across the product families listed below. Please note that a My Oracle Support (MOS) note summarizing the content of this Critical Patch Update and other Oracle Software Security Assurance activities is located at July 2026 Critical Patch Update: Executive Summary and Analysis.

2026-11-08 10:22 UTC
Oracle Critical Security Patch Update Advisory - September 2026

web:www.oracle.com

Oracle Database Server Client-Only Installations The following Oracle Database Server vulnerabilities included in this Critical Security Patch Update affect client-only installations: CVE - 2026 -83348 and CVE - 2026 -83156. Oracle Autonomous Health Framework Risk Matrix This Critical Security Patch Update contains 2 new security patches, plus additional third party patches noted below, for Oracle ...

2026-11-08 10:22 UTC

AI Forensic Analysis

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-123604.json.

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:cargo/hickory-resolver",
          "product": "hickory-dns",
          "vendor": "hickory-dns",
          "versions": [
            {
              "lessThan": "0.26.2",
              "status": "affected",
              "version": "0.26.0-beta.1",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "0.26.2",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
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          "type": "reporter",
          "value": "qifan-sailboat"
        }
      ],
      "datePublic": "2026-09-03T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 8.7,
            "baseSeverity": "HIGH",
            "exploitMaturity": "NOT_DEFINED",
            "privilegesRequired": "NONE",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "NONE",
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            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
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            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "format": "CVSS"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-835",
              "description": "Loop with Unreachable Exit Condition ('Infinite Loop')",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-11-08T01:38:31.351Z",
        "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "shortName": "VulnCheck"
      },
      "references": [
        {
          "name": "GitHub Security Advisory (GHSA-6w6g-hm98-mhgm)",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-6w6g-hm98-mhgm"
        },
        {
          "name": "VulnCheck Advisory: Hickory DNS 0.26.0-beta.1 before 0.26.2 Resource Exhaustion DoS via NameServerPool::try_send TC-Retry Loop",
          "tags": [
            "third-party-advisory"
          ],
          "url": "https://www.vulncheck.com/advisories/hickory-dns-0.26.0-beta.1-before-0.26.2-resource-exhaustion-dos-via-nameserverpool-try-send-tc-retry-loop"
        }
      ],
      "title": "Hickory DNS 0.26.0-beta.1 before 0.26.2 Resource Exhaustion DoS via NameServerPool::try_send TC-Retry Loop",
      "x_generator": {
        "engine": "vulncheck-endgame"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
    "assignerShortName": "VulnCheck",
    "cveId": "CVE-2026-123604",
    "datePublished": "2026-11-08T01:38:31.351Z",
    "dateReserved": "2026-11-06T01:00:16.506Z",
    "dateUpdated": "2026-11-08T01:38:31.351Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}