Mailvelope prior to 3.3.0 allows private key operations without user interaction via its client-API. By modifying an URL parameter in Mailvelope, an attacker is able to sign (and encrypt) arbitrary messages with Mailvelope, assuming the private key password is cached. A second vulnerability allows an attacker to decrypt an arbitrary message when the GnuPG backend is used in Mailvelope.
Severity
CVSS 3.1
6.5 medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
EPSS
0.9% chance of exploitation in the next 30 days; higher than 59% of CVEs (scores of 2026-10-31)