CVE-2020-26547: Monal

Critical severity, CVSS 9.8. EPSS: 0.5% chance of exploitation in the next 30 days.

Monal before 4.9 does not implement proper sender verification on MAM and Message Carbon (XEP-0280) results. This allows a remote attacker (able to send stanzas to a victim) to inject arbitrary messages into the local history, with full control over the sender and receiver displayed to the victim.

Affected products

• Monal Monal: before 4.9 (fixed in 4.9)

Published 2021-02-01. Last modified 2026-06-17.