CVE-2018-7537: Canonical Ubuntu Linux

Medium severity, CVSS 5.3. EPSS: 4.4% chance of exploitation in the next 30 days.

An issue was discovered in Django 2.0 before 2.0.3, 1.11 before 1.11.11, and 1.8 before 1.8.19. If django.utils.text.Truncator's chars() and words() methods were passed the html=True argument, they were extremely slow to evaluate certain inputs due to a catastrophic backtracking vulnerability in a regular expression. The chars() and words() methods are used to implement the truncatechars_html and truncatewords_html template filters, which were thus vulnerable.

Affected products

• Canonical Ubuntu Linux: version 14.04 only; version 16.04 only; version 17.10 only
• Debian Debian Linux: version 7.0 only; version 8.0 only; version 9.0 only
• Djangoproject Django: from 1.8, before 1.8.19 (fixed in 1.8.19); from 1.11, before 1.11.11 (fixed in 1.11.11); from 2.0, before 2.0.3 (fixed in 2.0.3)

Published 2018-03-09. Last modified 2026-06-17.