Vulnerability-Lookup

GHSA-R5WH-92FX-CV6J

Vulnerability from github – Published: 2026-10-14 12:31 – Updated: 2026-10-14 12:31

Details

When a SVCB or HTTPS RR has filled the wire format RDATA up to the brim, another ECH parameter may overwrite the stack, and once beyond the limit, the base64 decoder can write attacker controlled data of unlimited size. Zone files which are written out by NSD itself, such as for zones for which the NSD instance is secondary, will not be formatted like this. The zone file must be fed to NSD directly, (but it could come, for example, from an operator controlled provisioning system).

Severity

8.7 (High)


                  
                    CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Show details on source website

JSON

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{
  "affected": [],
  "aliases": [
    "CVE-2026-101338"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-121"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-14T11:16:57Z",
    "severity": "HIGH"
  },
  "details": "When a SVCB or HTTPS RR has filled the wire format RDATA up to the brim, another ECH parameter may overwrite the stack, and once beyond the limit, the base64 decoder can write attacker controlled data of unlimited size.  Zone files which are written out by NSD itself, such as for zones for which the NSD instance is secondary, will not be formatted like this. The zone file must be fed to NSD directly, (but it could come, for example, from an operator controlled provisioning system).",
  "id": "GHSA-r5wh-92fx-cv6j",
  "modified": "2026-10-14T12:31:32Z",
  "published": "2026-10-14T12:31:32Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-101338"
    },
    {
      "type": "WEB",
      "url": "https://www.nlnetlabs.nl/downloads/nsd/CVE-2026-101338.txt"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2026-101338 (GCVE-0-2026-101338)

Vulnerability from cvelistv5 – Published: 2026-10-14 10:56 – Updated: 2026-10-14 14:09

Title

Stack overwrite from a specially crafted and formatted SVCB or HTTPS RR

Summary

Severity

8.7 (High)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-14 14:09 UTC

CWE

CWE-121 - Stack-based Buffer Overflow

Assigner

NLnet Labs CNA

CNA scorecard B 82/100 over 61 records in the last 180 days details

References

1 reference

URL	Tags
https://www.nlnetlabs.nl/downloads/nsd/CVE-2026-1…	vendor-advisory

Impacted products

1 product

Vendor	Product	Version
NLnet Labs	NSD	Affected: 4.10.0 , < 4.15.3 (semver)

Date Public

2026-10-14 12:00

Credits

Qifan Zhang from Palo Alto Networks

Show details on NVD website

JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-101338",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-10-14T14:09:10.026829Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-10-14T14:09:20.163Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "NSD",
          "vendor": "NLnet Labs",
          "versions": [
            {
              "lessThan": "4.15.3",
              "status": "affected",
              "version": "4.10.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
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          "type": "finder",
          "value": "Qifan Zhang from Palo Alto Networks"
        }
      ],
      "datePublic": "2026-10-14T12:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "When a SVCB or HTTPS RR has filled the wire format RDATA up to the brim, another ECH parameter may overwrite the stack, and once beyond the limit, the base64 decoder can write attacker controlled data of unlimited size.  Zone files which are written out by NSD itself, such as for zones for which the NSD instance is secondary, will not be formatted like this. The zone file must be fed to NSD directly, (but it could come, for example, from an operator controlled provisioning system)."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "baseScore": 8.7,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
            "version": "4.0"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "When reading zone files, a specially crafted and format SVCB or HTTPS record cancause an out of bounds stack overwrite which can be exploited for execution of arbitrary commands."
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-121",
              "description": "CWE-121 Stack-based Buffer Overflow",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-14T10:56:28.223Z",
        "orgId": "206fc3a0-e175-490b-9eaa-a5738056c9f6",
        "shortName": "NLnet Labs"
      },
      "references": [
        {
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://www.nlnetlabs.nl/downloads/nsd/CVE-2026-101338.txt"
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "value": "This issue is fixed in 4.15.3 and all later versions."
        }
      ],
      "timeline": [
        {
          "lang": "en",
          "time": "2026-08-13T08:12:00.000Z",
          "value": "Issue reported by Qifan Zhang"
        },
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          "lang": "en",
          "time": "2026-09-27T15:03:00.000Z",
          "value": "NLnet Labs shares patch"
        },
        {
          "lang": "en",
          "time": "2026-09-28T21:21:00.000Z",
          "value": "Qifan Zhang verifies patch"
        },
        {
          "lang": "en",
          "time": "2026-10-14T12:00:00.000Z",
          "value": "Fix released with version 4.15.3"
        }
      ],
      "title": "Stack overwrite from a specially crafted and formatted SVCB or HTTPS RR",
      "x_generator": {
        "engine": "cvelib 1.8.0"
      }
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  },
  "cveMetadata": {
    "assignerOrgId": "206fc3a0-e175-490b-9eaa-a5738056c9f6",
    "assignerShortName": "NLnet Labs",
    "cveId": "CVE-2026-101338",
    "datePublished": "2026-10-14T10:56:28.223Z",
    "dateReserved": "2026-09-28T14:39:03.778Z",
    "dateUpdated": "2026-10-14T14:09:20.163Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

Vulnerability timeline

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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