CVE-2026-32303

High

Published: 20 March 2026

Published

20 March 2026

Modified

26 March 2026

KEV Added

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Patch

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CVSS Score 7.6 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N

EPSS Score 0.0002 5.4th percentile

Risk Priority 15 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-32303 is a high-severity Origin Validation Error (CWE-346) vulnerability in Cryptomator Cryptomator. Its CVSS base score is 7.6 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Steal Application Access Token (T1528); ranked at the 5.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified are NIST 800-53 SI-2 (Flaw Remediation) and SI-7 (Software, Firmware, and Information Integrity).

Threat & Defense at a Glance

What attackers do: exploitation maps to Steal Application Access Token (T1528). What defenders deploy: see the NIST 800-53 controls recommended below.

Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

SI-7 Software, Firmware, and Information Integrity good match

preventdetect

Requires integrity verification of the vault.cryptomator configuration file to detect tampering and prevent trusting malicious endpoints specified within it.

SI-2 Flaw Remediation good match

prevent

Mandates timely flaw remediation by patching Cryptomator to version 1.19.1 or later, which implements the missing integrity checks for the vault configuration.

CM-3 Configuration Change Control partial match

prevent

Establishes processes to control and approve changes to the vault.cryptomator file, reducing the attacker's ability to tamper with it despite low privileges.

MITRE ATT&CK Enterprise TechniquesAI

T1528 Steal Application Access Token Credential Access

Adversaries can steal application access tokens as a means of acquiring credentials to access remote systems and resources.

attack.mitre.org →

Why these techniques?

The vulnerability's core impact is enabling token exfiltration to a malicious endpoint via tampered vault config and missing endpoint validation, which directly maps to stealing application access tokens (T1528) for subsequent unauthorized API/Hub access.

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

NVD Description

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.

Deeper analysisAI

CVE-2026-32303 is an integrity check vulnerability in Cryptomator, an application that encrypts data stored on cloud infrastructure. It affects versions prior to 1.19.1, particularly the vault configuration file known as vault.cryptomator. The flaw enables an attacker to tamper with this file, resulting in a man-in-the-middle vulnerability during the Hub key loading mechanism. Prior to the fix, the client trusted endpoints specified in the vault config without performing host authenticity checks, which could facilitate token exfiltration by combining a legitimate authentication endpoint with a malicious API endpoint. The vulnerability carries a CVSS v3.1 base score of 7.6 (AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N) and is associated with CWEs 346, 354, 451, and 923.

Exploitation targets users unlocking Hub-backed vaults using affected Cryptomator client versions in environments where an attacker can modify the vault.cryptomator file. The attacker requires low privileges (PR:L) and relies on network access (AV:N) with low attack complexity (AC:L), but user interaction is needed, such as unlocking the vault (UI:R). Successful attacks lead to high confidentiality impact (C:H) through token exfiltration, with the scope changing (S:C) due to the altered trust in endpoints.

Cryptomator addressed this issue in version 1.19.1. Mitigation details are documented in the patching commit at https://github.com/cryptomator/cryptomator/commit/6b82abcd80449a30b561d823193f9ecea542a625, pull request #4179 at https://github.com/cryptomator/cryptomator/pull/4179, release notes at https://github.com/cryptomator/cryptomator/releases/tag/1.19.1, and the security advisory at https://github.com/cryptomator/cryptomator/security/advisories/GHSA-34rf-rwr3-7g43. Security practitioners should ensure clients are updated to 1.19.1 or later and verify vault configuration integrity in untrusted environments.