CVE-2026-32303
Cryptomator ≤ 1.19.1
Raw vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:NCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
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 Adversary-in-the-Middle (T1557); ranked at the 1th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to AC-4 (Information Flow Enforcement) and IA-3 (Device Identification and Authentication) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
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.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-13746
Vulnerability Data
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…
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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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 18 hardening rules · 4 OS baselines
V8.4.1V10.4.12V10.5.5V12.3.5
Mitigating Controls (NIST 800-53 r5) AI
Requires unique identification and authentication of devices before establishing a communications session.
Requires integrity verification tools that detect unauthorized changes when checksum validation is missing or flawed.
Information flow enforcement directly requires validating the source of data before allowing transmission or receipt.
Mandates cryptographic mechanisms that include integrity protection, preventing improper checksum validation.
Session authenticity mechanisms require validation that communications originate from the expected party.
Requires protection of transmitted information integrity, directly mandating correct validation of integrity checks.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Network segmentation and access controls directly enforce communication only with intended endpoints.
Authentication directly verifies the source of users/services/hardware, mitigating origin validation failures.
Verifying identity assertions enforces origin validation for conveyed claims.
Requires cryptographic hashes and signatures that directly enforce integrity-check validation for data at rest.
Requires cryptographic hashes and signatures that directly enforce integrity-check validation for data in transit.
Secure SDLC practices directly address design and implementation of accurate, non-spoofable UI elements.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Cryptographic controls mandate integrity mechanisms whose correct validation directly prevents CWE-354.
Secure coding standards require proper implementation and validation of checksums or MACs.
Security testing can detect missing integrity validation but does not itself implement the control.
Secure authentication mechanisms ensure the product communicates only with intended, authenticated endpoints.
Security awareness training can teach users to recognize UI misrepresentation and phishing attempts.
Network security controls enforce origin validation at network boundaries.
Hardening callouts derived
Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).
Oracle Linux 8 (4 rules)
- V-248574 YUM must be configured to prevent the installation of patches, service packs, device drivers, or OL 8 system components that have not been digitally signed using a certificate that is recognized and approved by the organization. prevents CWE-346, CWE-354
- V-248575 OL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-346, CWE-354
- V-248827 OL 8 must not have the rsh-server package installed. prevents CWE-346, CWE-923
Oracle Linux 9 (1 rule)
- V-271523 OL 9 must check the GPG signature of locally installed software packages before installation. prevents CWE-354
RHEL 7 (3 rules)
- V-204447 The Red Hat Enterprise Linux operating system must prevent the installation of software, patches, service packs, device drivers, or operating system components from a repository without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-354
- V-204448 The Red Hat Enterprise Linux operating system must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-354
- V-204442 The Red Hat Enterprise Linux operating system must not have the rsh-server package installed. prevents CWE-923
RHEL 8 (4 rules)
- V-230264 RHEL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components from a repository without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-354
- V-230265 RHEL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-354
- V-230492 RHEL 8 must not have the rsh-server package installed. prevents CWE-923