CVE-2026-104733 PUBLISHED

User Impersonation/Authorization Bypass in XMPP Server ejabberd

Assigner: NCSC.ch
Reserved: 02.10.2026 Published: 02.10.2026 Updated: 02.10.2026

User Impersonation in ProcessOnes XMMP Server ejabberd <= 26.04 allows an attacker to impersonate arbitrary users via unvalidated authzid parameter in SASL-PLAIN mechanism.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:H/SC:H/SI:H/SA:H/E:P
CVSS Score: 7.4

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	High	Confidentiality	High
Attack Complexity	Low	Integrity	None	Integrity	High
Attack Requirements	None	Availability	High	Availability	High
Privileges Required	Low
User Interaction	None

CVSS 4.0

Product Status

Vendor	ProcessOne
Product	ejabberd
Versions	Default: unaffected affected from 0 to 26.04 (incl.)

Workarounds

Disable the SALS-PLAIN authentication mechanism

Solutions

Update to the latest version of ejabberd (26.07)

Credits

Marius Schwarz (NSIDE ATTACK LOGIC GmbH) finder

References

Problem Types

User Impersonation

Impacts

Authorization Bypass