CVE-2026-26028 Detail
Received
This CVE record has recently been published to the CVE List and has been included within the NVD dataset. DescriptionCryptPad is an end-to-end encrypted collaborative office suite. In versions prior to 2026.2.0, the HTML sanitizer in Diffmarked.js can be bypassed due to incomplete attribute filtering on restricted tags. The sanitizer validates only the src attribute of <iframe>, <video>, and <audio> elements, leaving all other attributes unchecked. As a result, an attacker can inject arbitrary HTML through srcdoc, completely defeating CryptPad's intended bounce sandboxing and enabling link injection or other interactive content within user-controlled documents. The root cause lies in how the sanitizer classifies and enforces tag restrictions: although it defines both forbidden and restricted tag lists, <iframe> is treated as "restricted" rather than "forbidden." Enforcement then inspects only the src attribute, so pairing a benign blob: src with a malicious srcdoc results in unrestricted rendering. This issue has been fixed in version 2026.2.0. Metrics
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CVSS 4.0 Severity and Vector Strings:
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Quick InfoCVE Dictionary Entry:CVE-2026-26028 NVD Published Date: 05/20/2026 NVD Last Modified: 05/20/2026 Source: GitHub, Inc. |
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