Reusing a Nonce, Key Pair in Encryption in Habitica - #VU128137
Published: April 27, 2026
Vulnerability identifier: #VU128137
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: N/A
CWE-ID: CWE-323
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: HabitRPG
Affected software:
Habitica
Habitica
Detailed vulnerability description
The vulnerability allows a remote user to disclose sensitive information.
The vulnerability exists due to reusing a nonce in encryption in the encryption helper and group invitation handling logic when processing encrypted unsubscribe tokens and groupInvite parameters. A remote user can recover the keystream from a known-plaintext unsubscribe token and forge a crafted groupInvite ciphertext to disclose sensitive information.
User interaction is required because a new account must be registered with the crafted groupInvite parameter.
Remediation
Install security update from vendor's website.