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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-104480
StatePUBLISHED
AssignerBugcrowd
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-02 02:17:02 UTC
Updated2026-10-02 02:17:02 UTC
DescriptionDiscord 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.

Risk And Classification

Primary CVSS: v4.0 9.4 CRITICAL from 4ac701fe-44e9-4bcd-9585-dd6449257611

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

Problem Types: CWE-390 | CWE-863 | CWE-390 CWE-390 Detection of Error Condition Without Action | CWE-863 CWE-863 Incorrect Authorization

VersionSourceTypeScoreSeverityVector
4.04ac701fe-44e9-4bcd-9585-dd6449257611Secondary9.4CRITICALCVSS: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/C...
4.0CNACVSS9.4CRITICALCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
Present
Privileges Required
None
User Interaction
None
Confidentiality
High
Integrity
High
Availability
None
Sub Conf.
High
Sub Integrity
High
Sub Availability
None

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Discord Libdave affected 1.1.0 1.2.0 semver Not specified
CNA Discord Libdave affected 7b15f1fc16f159da0478aa6be909e38f1e957833 9686fbaea864aa19f0675e486672b6a77811b6a1 git Not specified

References

ReferenceSourceLinkTags
daveprotocol.com 4ac701fe-44e9-4bcd-9585-dd6449257611 daveprotocol.com
github.com/discord/libdave/releases/tag/v1.2.0/cpp 4ac701fe-44e9-4bcd-9585-dd6449257611 github.com
github.com/discord/libdave 4ac701fe-44e9-4bcd-9585-dd6449257611 github.com
github.com/discord/libdave/commit/9686fbaea864aa19f0675e486672b6a77811b6a1 4ac701fe-44e9-4bcd-9585-dd6449257611 github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: MDL (https://heartbreak.ing) (en)

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