CVE-2026-123588

Description

The recursive resolver in Hickory DNS (all versions of the hickory-recursor crate, and hickory-resolver 0.26.0 before 0.26.2) caches an empty connection pool when it follows a referral with no glue records and all queries for the name servers' IP addresses fail. An attacker able to spoof DNS responses can make these lookups fail, causing all subsequent queries for the affected zone to fail until the cache entry expires or is evicted.

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-754
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-2026-123588.json
Linked Threat: CVE-2026-123588 — Hickory DNS Recursive Resolver Denial of Service via Cached Empty Connection Pool

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-2026-119347

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

Affected products (2)

Vendor	Product	Versions	Platforms
hickory-dns	hickory-dns	`0` (affected)	—
hickory-dns	hickory-dns	`0.26.0` (affected), `0.26.2` (unaffected)	—

Vendor references (2)

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

GitHub Security Advisory (GHSA-9px7-7m25-f6q2) vendor-advisory
VulnCheck Advisory: Hickory DNS Recursive Resolver Denial of Service via Cached Empty Connection Pool 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.

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
Alpine OpenSSH Password Bypass (CVE-2026-123158): Check and Fix

web:devops-daily.com

Read-only check for CVE - 2026 -123158: is your Alpine sshd affected by the password authentication bypass, fixed, or still running the old daemon? Tested on Alpine 3.21 to 3.24 and edge.

2026-11-08 10:22 UTC
CVE-2026-123588: hickory-dns · Unchecked Error Condition

web:radar.offseq.com

Description CVE-2026-123588 is a high-severity vulnerability in Hickory DNS's recursive resolver affecting all versions of the hickory-recursor crate and hickory-resolver versions before 0.26.2. The resolver caches an empty connection pool when it encounters a referral with no glue records and all IP address queries for the name servers fail.

2026-11-08 10:22 UTC
Cisco Meraki Security Hardening Release: October 2026

web:sec.cloudapps.cisco.com

As part of Cisco's ongoing commitment to proactive security and product quality, engineering teams conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities. These vulnerabilities were found during internal testing and are not known to be actively exploited. To assist customers in patching ...

2026-11-08 10:22 UTC
CVE-2026-123588 - Hickory DNS Caching Flaw Enables Zone-Wide…

web:vulmon.com

Vulnerability Summary Hickory DNS, specifically the hickory-recursor crate (all versions) and hickory-resolver versions 0.26.0 before 0.26.2, caches an empty connection pool. This occurs when it processes a referral lacking glue records and all attempts to query name server IP addresses fail. An attacker who can spoof DNS responses can force these lookups to fail. Consequently, all subsequent ...

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
Vulnerability Remediation vs. Mitigation Explained

web:www.armorcode.com

The Strategic Decision Matrix: When to Remediate vs. Mitigate Prioritization paralysis happens when everything looks urgent. Deciding between remediation and mitigation requires looking past the CVSS score and incorporating actual business context. The framework below walks through the same four factors covered in this section: exploitability, patch availability, asset criticality, and ...

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 Security Patch Update Advisory - September 2026

web:www.oracle.com

Prior Critical Patch Update and Critical Security Patch Update advisories should be reviewed for information regarding earlier published security patches. Refer to Critical Patch Updates, Critical Security Patch Updates, Security Alerts and Bulletins for information about Oracle Security advisories.

2026-11-08 10:22 UTC
Vulnerability Remediation vs. Mitigation: What are the Differences?

web:www.secure.com

Remediation fully removes a vulnerability by fixing its root cause — through a patch , code fix , or system replacement. Mitigation reduces the risk of exploitation without removing the flaw itself, using controls like network segmentation or access restrictions.

2026-11-08 10:22 UTC

AI Forensic Analysis

Only Available for Registered Users. Sign in to view.

Raw JSON

The full cvelistV5 record. Download as CVE-2026-123588.json.

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:cargo/hickory-recursor",
          "product": "hickory-dns",
          "vendor": "hickory-dns",
          "versions": [
            {
              "lessThanOrEqual": "0.26.0-alpha.1",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:cargo/hickory-resolver",
          "product": "hickory-dns",
          "vendor": "hickory-dns",
          "versions": [
            {
              "lessThan": "0.26.2",
              "status": "affected",
              "version": "0.26.0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "0.26.2",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "reporter",
          "value": "qifan-sailboat"
        }
      ],
      "datePublic": "2026-09-03T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "The recursive resolver in Hickory DNS (all versions of the hickory-recursor crate, and hickory-resolver 0.26.0 before 0.26.2) caches an empty connection pool when it follows a referral with no glue records and all queries for the name servers' IP addresses fail. An attacker able to spoof DNS responses can make these lookups fail, causing all subsequent queries for the affected zone to fail until the cache entry expires or is evicted."
        }
      ],
      "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",
            "vulnIntegrityImpact": "NONE",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "format": "CVSS"
        },
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "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-754",
              "description": "Improper Check for Unusual or Exceptional Conditions",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-11-08T01:38:20.288Z",
        "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "shortName": "VulnCheck"
      },
      "references": [
        {
          "name": "GitHub Security Advisory (GHSA-9px7-7m25-f6q2)",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-9px7-7m25-f6q2"
        },
        {
          "name": "VulnCheck Advisory: Hickory DNS Recursive Resolver Denial of Service via Cached Empty Connection Pool",
          "tags": [
            "third-party-advisory"
          ],
          "url": "https://www.vulncheck.com/advisories/hickory-dns-recursive-resolver-denial-of-service-via-cached-empty-connection-pool"
        }
      ],
      "title": "Hickory DNS Recursive Resolver Denial of Service via Cached Empty Connection Pool",
      "x_generator": {
        "engine": "vulncheck-endgame"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
    "assignerShortName": "VulnCheck",
    "cveId": "CVE-2026-123588",
    "datePublished": "2026-11-08T01:38:20.288Z",
    "dateReserved": "2026-11-06T00:57:31.045Z",
    "dateUpdated": "2026-11-08T01:38:20.288Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}