Cryptomator <1.19.1: Config Integrity Bypass Enables MITM
CVE-2026-32303 Published on March 20, 2026
Cryptomator: Tampered vault configuration allows MITM attack on Hub API
Cryptomator encrypts data being stored on cloud infrastructure. Prior to version 1.19.1, an integrity check vulnerability allows an attacker to tamper with the vault configuration file leading to a man-in-the-middle vulnerability in Hub key loading mechanism. Before this fix, the client trusted endpoints from the vault config without host authenticity checks, which could allow token exfiltration by mixing a legitimate auth endpoint with a malicious API endpoint. Impacted are users unlocking Hub-backed vaults with affected client versions in environments where an attacker can alter the vault.cryptomator file. This issue has been patched in version 1.19.1.
Vulnerability Analysis
CVE-2026-32303 can be exploited with network access, requires user interaction and a small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality, with no impact on integrity, and no impact on availability.
Weakness Types
Origin Validation Error
The software does not properly verify that the source of data or communication is valid.
Improper Validation of Integrity Check Value
The software does not validate or incorrectly validates the integrity check values or "checksums" of a message. This may prevent it from detecting if the data has been modified or corrupted in transmission. Improper validation of checksums before use results in an unnecessary risk that can easily be mitigated. The protocol specification describes the algorithm used for calculating the checksum. It is then a simple matter of implementing the calculation and verifying that the calculated checksum and the received checksum match. Improper verification of the calculated checksum and the received checksum can lead to far greater consequences.
User Interface (UI) Misrepresentation of Critical Information
The user interface (UI) does not properly represent critical information to the user, allowing the information - or its source - to be obscured or spoofed. This is often a component in phishing attacks.
Improper Restriction of Communication Channel to Intended Endpoints
The software establishes a communication channel to (or from) an endpoint for privileged or protected operations, but it does not properly ensure that it is communicating with the correct endpoint.
Affected Versions
cryptomator Version < 1.19.1 is affected by CVE-2026-32303Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.