CVE-2022-31103: Lettersanitizer Project Lettersanitizer

High severity, CVSS 7.5. EPSS: 1.5% chance of exploitation in the next 30 days.

lettersanitizer is a DOM-based HTML email sanitizer for in-browser email rendering. All versions of lettersanitizer below 1.0.2 are affected by a denial of service issue when processing a CSS at-rule `@keyframes`. This package is depended on by [react-letter](https://github.com/mat-sz/react-letter), therefore everyone using react-letter is also at risk. The problem has been patched in version 1.0.2.

Affected products

• Lettersanitizer Project Lettersanitizer: before 1.0.2 (fixed in 1.0.2)

Published 2022-06-27. Last modified 2026-06-17.