An issue was discovered in urllib2 in Python 2.x through 2.7.17 and urllib in Python 3.x through 3.8.0.

Summary

An issue was discovered in urllib2 in Python 2.x through 2.7.17 and urllib in Python 3.x through 3.8.0. CRLF injection is possible if the attacker controls a url parameter, as demonstrated by the first argument to urllib.request.urlopen with \r\n (specifically in the host component of a URL) followed by an HTTP header. This is similar to the CVE-2019-9740 query string issue and the CVE-2019-9947 path string issue. (This is not exploitable when glibc has CVE-2016-10739 fixed.). This is fixed in: v2.7.18, v2.7.18rc1; v3.5.10, v3.5.10rc1; v3.6.11, v3.6.11rc1, v3.6.12; v3.7.8, v3.7.8rc1, v3.7.9; v3.8.3, v3.8.3rc1, v3.8.4, v3.8.4rc1, v3.8.5, v3.8.6, v3.8.6rc1.

Timeline

1. Oct 23, 2019, 4:31 PM UTCCVE published
2. Oct 7, 2026, 6:00 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: partial

3. Oct 14, 2026, 6:54 AM UTCRecord last updated

Affected versions

No affected packages have been listed by the sources.

References 13