Vulnerability-Lookup

GHSA-3Q99-X36R-RCHH

Vulnerability from github – Published: 2026-10-02 03:31 – Updated: 2026-10-02 03:31

Details

Discord libdave before 1.2.0 did not reject an MLS Welcome message when the resulting group roster contained an unrecognized participant. An attacker in control of the DAVE signaling path (the voice gateway, or an equivalent position able to add, alter, or withhold signaling messages to a client) could cause affected clients to accept an unauthorized member into the end-to-end encrypted media session, compromising the confidentiality and integrity of audio and video.

Severity

9.4 (Critical)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-104480"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-390"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-02T02:17:02Z",
    "severity": "CRITICAL"
  },
  "details": "Discord libdave before 1.2.0 did not reject an MLS Welcome message when the resulting group roster contained an unrecognized participant. An attacker in control of the DAVE signaling path (the voice gateway, or an equivalent position able to add, alter, or withhold signaling messages to a client) could cause affected clients to accept an unauthorized member into the end-to-end encrypted media session, compromising the confidentiality and integrity of audio and video.",
  "id": "GHSA-3q99-x36r-rchh",
  "modified": "2026-10-02T03:31:10Z",
  "published": "2026-10-02T03:31:10Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-104480"
    },
    {
      "type": "WEB",
      "url": "https://github.com/discord/libdave/commit/9686fbaea864aa19f0675e486672b6a77811b6a1"
    },
    {
      "type": "WEB",
      "url": "https://daveprotocol.com"
    },
    {
      "type": "WEB",
      "url": "https://github.com/discord/libdave"
    },
    {
      "type": "WEB",
      "url": "https://github.com/discord/libdave/releases/tag/v1.2.0/cpp"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/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-2026-104480 (GCVE-0-2026-104480)

Vulnerability from cvelistv5 – Published: 2026-10-02 00:57 – Updated: 2026-10-02 00:57

Title

Improper MLS Welcome roster validation in Discord libdave allows unauthorized group membership

Summary

Severity

9.4 (Critical)


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

CWE

CWE-390 - Detection of Error Condition Without Action
CWE-863 - Incorrect Authorization

Assigner

Bugcrowd mitre root Scorecard

References

4 references

URL	Tags
https://github.com/discord/libdave/commit/9686fba…	patch
https://github.com/discord/libdave/releases/tag/v…	release-notes
https://daveprotocol.com/	technical-description
https://github.com/discord/libdave	product

Impacted products

1 product

Vendor	Product	Version
Discord	libdave	Affected: 1.1.0 , < 1.2.0 (semver) Affected: 7b15f1fc16f159da0478aa6be909e38f1e957833 , < 9686fbaea864aa19f0675e486672b6a77811b6a1 (git)

Credits

MDL (https://heartbreak.ing)

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JSON

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "collectionURL": "https://github.com",
          "defaultStatus": "unaffected",
          "modules": [
            "C++ library"
          ],
          "packageName": "discord/libdave",
          "product": "libdave",
          "programFiles": [
            "cpp/src/mls/session.cpp"
          ],
          "programRoutines": [
            {
              "name": "discord::dave::mls::Session::VerifyWelcomeState"
            }
          ],
          "repo": "https://github.com/discord/libdave",
          "vendor": "Discord",
          "versions": [
            {
              "lessThan": "1.2.0",
              "status": "affected",
              "version": "1.1.0",
              "versionType": "semver"
            },
            {
              "lessThan": "9686fbaea864aa19f0675e486672b6a77811b6a1",
              "status": "affected",
              "version": "7b15f1fc16f159da0478aa6be909e38f1e957833",
              "versionType": "git"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "MDL (https://heartbreak.ing)"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Discord libdave before 1.2.0 did not reject an MLS Welcome message when the resulting group roster contained an unrecognized participant. An attacker in control of the DAVE signaling path (the voice gateway, or an equivalent position able to add, alter, or withhold signaling messages to a client) could cause affected clients to accept an unauthorized member into the end-to-end encrypted media session, compromising the confidentiality and integrity of audio and video."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "baseScore": 9.4,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N",
            "version": "4.0"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-390",
              "description": "CWE-390 Detection of Error Condition Without Action",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-863",
              "description": "CWE-863 Incorrect Authorization",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-02T00:57:55.648Z",
        "orgId": "4ac701fe-44e9-4bcd-9585-dd6449257611",
        "shortName": "Bugcrowd"
      },
      "references": [
        {
          "name": "[cpp] restore strict validation of MLS welcome state",
          "tags": [
            "patch"
          ],
          "url": "https://github.com/discord/libdave/commit/9686fbaea864aa19f0675e486672b6a77811b6a1"
        },
        {
          "name": "libdave v1.2.0 release notes",
          "tags": [
            "release-notes"
          ],
          "url": "https://github.com/discord/libdave/releases/tag/v1.2.0/cpp"
        },
        {
          "name": "Discord Audio and Video End-to-End Encryption (DAVE) Protocol Whitepaper",
          "tags": [
            "technical-description"
          ],
          "url": "https://daveprotocol.com/"
        },
        {
          "tags": [
            "product"
          ],
          "url": "https://github.com/discord/libdave"
        }
      ],
      "title": "Improper MLS Welcome roster validation in Discord libdave allows unauthorized group membership",
      "x_generator": {
        "engine": "cvelib 1.8.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "4ac701fe-44e9-4bcd-9585-dd6449257611",
    "assignerShortName": "Bugcrowd",
    "cveId": "CVE-2026-104480",
    "datePublished": "2026-10-02T00:57:55.648Z",
    "dateReserved": "2026-10-02T00:57:11.860Z",
    "dateUpdated": "2026-10-02T00:57:55.648Z",
    "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.

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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

GHSA-3Q99-X36R-RCHH

CVE-2026-104480 (GCVE-0-2026-104480)

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