PT-2026-42220 · Cryptpad · Cryptpad

Ixsly · Published 2026-05-20 · Updated 2026-05-26 · CVE-2026-26028

Positive Technologies (AI Summary)

CVSS v3.1

6.1

Medium

Base vector

AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Name of the Vulnerable Software and Affected Versions CryptPad versions prior to 2026.2.0

Description The HTML sanitizer in Diffmarked.js contains a flaw where it fails to properly filter attributes on restricted tags. While the sanitizer validates the src attribute for <iframe>, <video>, and <audio> elements, it does not check other attributes. This allows an attacker to inject arbitrary HTML using the srcdoc attribute, bypassing the intended bounce sandboxing and enabling link injection or other interactive content within user-controlled documents. The issue occurs because <iframe> is classified as a restricted tag rather than a forbidden one, and the enforcement mechanism only inspects the src attribute.

Recommendations Update to version 2026.2.0.

Fix

Improper Encoding or Escaping of Output

XSS

Weakness Enumeration

CWE-116

CWE-79

Related Identifiers

CVE-2026-26028

GHSA-G2G4-47GV-P72V

Affected Products

Cryptpad

References · 6

• https://osv.dev/vulnerability/GHSA-g2g4-47gv-p72v · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-26028 · Security Note
• https://github.com/cryptpad/cryptpad · Note
• https://github.com/cryptpad/cryptpad/releases/tag/2026.2.0 · Note
• https://github.com/cryptpad/cryptpad/security/advisories/GHSA-g2g4-47gv-p72v · Note
• https://t.me/CVEtracker/54414 · Telegram Post