CVE-2026-46582 (GCVE-0-2026-46582)

Vulnerability from cvelistv5 – Published: 2026-07-22 13:07 – Updated: 2026-07-22 18:56
VLAI
Title
A wildcard replay, as another piece of data, triggers poisoning in the serve expired reply path
Summary
In NLnet Labs Unbound 1.6.0 up to and including 1.25.1, a replay of a wildcard rrset as another piece of data, could be briefly considered DNSSEC secure based only on the RRSIG validation and stored into cache, before later validation treats it as bogus based on NSEC validation. When the resolving thread puts secure on the rrset, and another thread that is on the serve expired path then picks up the updated rrset contents with the secure status for a reply, it can be used to change a specific record, next to a wildcard that could be covered by the wildcard, into the wildcard. A malicious actor can exploit the possible poisonous effect by having any DNSSEC-singed domain (irrelevant to the victim domain) and a CNAME wrapper record that points to a record next to a wildcard (that could be covered by the wildcard). Then quering Unbound for the wildcard sibling record would seed the secure message. A later (after expiry) query for the CNAME wrapper would need to resolve the target sibling record. If the wildcard replay is injected into the response, the wildcard rrset will update the expired sibling record with a secure status before completing proper wildcard validation with NSEC records and eventually treating the CNAME wrapper answer as bogus. The updated poisoned rrset is now secure and points to the wildcard. This vulnerability is explicit for the serve expired path and needs injection of the signed wildcard rrset without the NSEC accompanying rrset.
Severity
3.7 (Low)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
  • CWE-358 - Improperly Implemented Security Check for Standard
Assigner
References
Impacted products
Vendor Product Version
NLnet Labs Unbound Affected: 1.6.0 , < 1.25.2 (semver)
Create a notification for this product.
Date Public
2026-07-22 00:00
Credits
Qifan Zhang (Palo Alto Networks)
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-46582",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-22T18:56:31.700965Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-07-22T18:56:40.376Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Unbound",
          "vendor": "NLnet Labs",
          "versions": [
            {
              "lessThan": "1.25.2",
              "status": "affected",
              "version": "1.6.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Qifan Zhang (Palo Alto Networks)"
        }
      ],
      "datePublic": "2026-07-22T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "In NLnet Labs Unbound 1.6.0 up to and including 1.25.1, a replay of a wildcard rrset as another piece of data, could be briefly considered DNSSEC secure based only on the RRSIG validation and stored into cache, before later validation treats it as bogus based on NSEC validation. When the resolving thread puts secure on the rrset, and another thread that is on the serve expired path then picks up the updated rrset contents with the secure status for a reply, it can be used to change a specific record, next to a wildcard that could be covered by the wildcard, into the wildcard. A malicious actor can exploit the possible poisonous effect by having any DNSSEC-singed domain (irrelevant to the victim domain) and a CNAME wrapper record that points to a record next to a wildcard (that could be covered by the wildcard). Then quering Unbound for the wildcard sibling record would seed the secure message. A later (after expiry) query for the CNAME wrapper would need to resolve the target sibling record. If the wildcard replay is injected into the response, the wildcard rrset will update the expired sibling record with a secure status before completing proper wildcard validation with NSEC records and eventually treating the CNAME wrapper answer as bogus. The updated poisoned rrset is now secure and points to the wildcard. This vulnerability is explicit for the serve expired path and needs injection of the signed wildcard rrset without the NSEC accompanying rrset."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 3.7,
            "baseSeverity": "LOW",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-358",
              "description": "CWE-358: Improperly Implemented Security Check for Standard",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-22T13:07:40.588Z",
        "orgId": "206fc3a0-e175-490b-9eaa-a5738056c9f6",
        "shortName": "NLnet Labs"
      },
      "references": [
        {
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-46582.txt"
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "value": "This issue is fixed starting with version 1.25.2"
        }
      ],
      "timeline": [
        {
          "lang": "en",
          "time": "2026-05-16T00:00:00.000Z",
          "value": "Issue reported by Qifan Zhang"
        },
        {
          "lang": "en",
          "time": "2026-06-09T00:00:00.000Z",
          "value": "NLnet Labs shares patch"
        },
        {
          "lang": "en",
          "time": "2026-06-13T00:00:00.000Z",
          "value": "Qifan Zhang verifies patch"
        },
        {
          "lang": "en",
          "time": "2026-07-22T00:00:00.000Z",
          "value": "Fixes released with version 1.25.2"
        }
      ],
      "title": "A wildcard replay, as another piece of data, triggers poisoning in the serve expired reply path",
      "x_generator": {
        "engine": "cvelib 1.8.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "206fc3a0-e175-490b-9eaa-a5738056c9f6",
    "assignerShortName": "NLnet Labs",
    "cveId": "CVE-2026-46582",
    "datePublished": "2026-07-22T13:07:40.588Z",
    "dateReserved": "2026-06-22T10:11:10.536Z",
    "dateUpdated": "2026-07-22T18:56:40.376Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-46582",
      "date": "2026-07-23",
      "epss": "0.00256",
      "percentile": "0.17123"
    },
    "microsoft_vex": {
      "current_release_date": "2026-07-23T01:04:32.000Z",
      "cve": "CVE-2026-46582",
      "id": "msrc_CVE-2026-46582",
      "initial_release_date": "2026-07-23T01:04:32.000Z",
      "product_status:known_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "A wildcard replay, as another piece of data, triggers poisoning in the serve expired reply path",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-46582.json",
      "version": "1"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-46582\",\"sourceIdentifier\":\"sep@nlnetlabs.nl\",\"published\":\"2026-07-22T14:17:19.397\",\"lastModified\":\"2026-07-22T20:33:11.590\",\"vulnStatus\":\"Undergoing Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In NLnet Labs Unbound 1.6.0 up to and including 1.25.1, a replay of a wildcard rrset as another piece of data, could be briefly considered DNSSEC secure based only on the RRSIG validation and stored into cache, before later validation treats it as bogus based on NSEC validation. When the resolving thread puts secure on the rrset, and another thread that is on the serve expired path then picks up the updated rrset contents with the secure status for a reply, it can be used to change a specific record, next to a wildcard that could be covered by the wildcard, into the wildcard. A malicious actor can exploit the possible poisonous effect by having any DNSSEC-singed domain (irrelevant to the victim domain) and a CNAME wrapper record that points to a record next to a wildcard (that could be covered by the wildcard). Then quering Unbound for the wildcard sibling record would seed the secure message. A later (after expiry) query for the CNAME wrapper would need to resolve the target sibling record. If the wildcard replay is injected into the response, the wildcard rrset will update the expired sibling record with a secure status before completing proper wildcard validation with NSEC records and eventually treating the CNAME wrapper answer as bogus. The updated poisoned rrset is now secure and points to the wildcard. This vulnerability is explicit for the serve expired path and needs injection of the signed wildcard rrset without the NSEC accompanying rrset.\"}],\"affected\":[{\"source\":\"sep@nlnetlabs.nl\",\"affectedData\":[{\"vendor\":\"NLnet Labs\",\"product\":\"Unbound\",\"defaultStatus\":\"unaffected\",\"versions\":[{\"version\":\"1.6.0\",\"lessThan\":\"1.25.2\",\"versionType\":\"semver\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"sep@nlnetlabs.nl\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N\",\"baseScore\":3.7,\"baseSeverity\":\"LOW\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"HIGH\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"LOW\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":2.2,\"impactScore\":1.4}],\"ssvcV203\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"ssvcData\":{\"timestamp\":\"2026-07-22T18:56:31.700965Z\",\"id\":\"CVE-2026-46582\",\"options\":[{\"exploitation\":\"none\"},{\"automatable\":\"no\"},{\"technicalImpact\":\"partial\"}],\"role\":\"CISA Coordinator\",\"version\":\"2.0.3\"}}]},\"weaknesses\":[{\"source\":\"sep@nlnetlabs.nl\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-358\"}]}],\"references\":[{\"url\":\"https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-46582.txt\",\"source\":\"sep@nlnetlabs.nl\"}]}}",
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-46582\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-07-22T18:56:31.700965Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-07-22T18:56:35.746Z\"}}], \"cna\": {\"title\": \"A wildcard replay, as another piece of data, triggers poisoning in the serve expired reply path\", \"credits\": [{\"lang\": \"en\", \"type\": \"finder\", \"value\": \"Qifan Zhang (Palo Alto Networks)\"}], \"metrics\": [{\"format\": \"CVSS\", \"cvssV3_1\": {\"version\": \"3.1\", \"baseScore\": 3.7, \"baseSeverity\": \"LOW\", \"vectorString\": \"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N\"}, \"scenarios\": [{\"lang\": \"en\", \"value\": \"GENERAL\"}]}], \"affected\": [{\"vendor\": \"NLnet Labs\", \"product\": \"Unbound\", \"versions\": [{\"status\": \"affected\", \"version\": \"1.6.0\", \"lessThan\": \"1.25.2\", \"versionType\": \"semver\"}], \"defaultStatus\": \"unaffected\"}], \"timeline\": [{\"lang\": \"en\", \"time\": \"2026-05-16T00:00:00.000Z\", \"value\": \"Issue reported by Qifan Zhang\"}, {\"lang\": \"en\", \"time\": \"2026-06-09T00:00:00.000Z\", \"value\": \"NLnet Labs shares patch\"}, {\"lang\": \"en\", \"time\": \"2026-06-13T00:00:00.000Z\", \"value\": \"Qifan Zhang verifies patch\"}, {\"lang\": \"en\", \"time\": \"2026-07-22T00:00:00.000Z\", \"value\": \"Fixes released with version 1.25.2\"}], \"solutions\": [{\"lang\": \"en\", \"value\": \"This issue is fixed starting with version 1.25.2\"}], \"datePublic\": \"2026-07-22T00:00:00.000Z\", \"references\": [{\"url\": \"https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-46582.txt\", \"tags\": [\"vendor-advisory\"]}], \"x_generator\": {\"engine\": \"cvelib 1.8.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"In NLnet Labs Unbound 1.6.0 up to and including 1.25.1, a replay of a wildcard rrset as another piece of data, could be briefly considered DNSSEC secure based only on the RRSIG validation and stored into cache, before later validation treats it as bogus based on NSEC validation. When the resolving thread puts secure on the rrset, and another thread that is on the serve expired path then picks up the updated rrset contents with the secure status for a reply, it can be used to change a specific record, next to a wildcard that could be covered by the wildcard, into the wildcard. A malicious actor can exploit the possible poisonous effect by having any DNSSEC-singed domain (irrelevant to the victim domain) and a CNAME wrapper record that points to a record next to a wildcard (that could be covered by the wildcard). Then quering Unbound for the wildcard sibling record would seed the secure message. A later (after expiry) query for the CNAME wrapper would need to resolve the target sibling record. If the wildcard replay is injected into the response, the wildcard rrset will update the expired sibling record with a secure status before completing proper wildcard validation with NSEC records and eventually treating the CNAME wrapper answer as bogus. The updated poisoned rrset is now secure and points to the wildcard. This vulnerability is explicit for the serve expired path and needs injection of the signed wildcard rrset without the NSEC accompanying rrset.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-358\", \"description\": \"CWE-358: Improperly Implemented Security Check for Standard\"}]}], \"providerMetadata\": {\"orgId\": \"206fc3a0-e175-490b-9eaa-a5738056c9f6\", \"shortName\": \"NLnet Labs\", \"dateUpdated\": \"2026-07-22T13:07:40.588Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-46582\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-07-22T18:56:40.376Z\", \"dateReserved\": \"2026-06-22T10:11:10.536Z\", \"assignerOrgId\": \"206fc3a0-e175-490b-9eaa-a5738056c9f6\", \"datePublished\": \"2026-07-22T13:07:40.588Z\", \"assignerShortName\": \"NLnet Labs\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.