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Findings

CVE-2019-9740

An issue was discovered in urllib2 in Python 2.x through 2.7.16 and urllib in Python 3.x through 3.7.3.

Published Mar 13, 2019 · updated Oct 14, 2026 · python python

An issue was discovered in urllib2 in Python 2.x through 2.7.16 and urllib in Python 3.x through 3.7.3. 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 query string after a ? character) followed by an HTTP header or a Redis command. This is fixed in: v2.7.17, v2.7.17rc1, v2.7.18, v2.7.18rc1; v3.5.10, v3.5.10rc1, v3.5.8, v3.5.8rc1, v3.5.8rc2, v3.5.9; v3.6.10, v3.6.10rc1, v3.6.11, v3.6.11rc1, v3.6.12, v3.6.9, v3.6.9rc1; v3.7.4, v3.7.4rc1, v3.7.4rc2, v3.7.5, v3.7.5rc1, v3.7.6, v3.7.6rc1, v3.7.7, v3.7.7rc1, v3.7.8, v3.7.8rc1, v3.7.9.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 13, 2019 · NIST NVD

    Detected

    An issue was discovered in urllib2 in Python 2.x through 2.7.16 and urllib in Python 3.x through 3.7.3. 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 query string after a ? character) followed by an HTTP header or a Redis command. This is fixed in: v2.7.17, v2.7.17rc1, v2.7.18, v2.

  2. Oct 14, 2026 · NIST NVD

    Updated

    An issue was discovered in urllib2 in Python 2.x through 2.7.16 and urllib in Python 3.x through 3.7.3. 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 query string after a ? character) followed by an HTTP header or a Redis command. This is fixed in: v2.7.17, v2.7.17rc1, v2.7.18, v2.

Affected

  • cpe python/pythonversion unspecified

Sources

  • CVE.orgCVE-2019-9740

    Official CVE identifier

    cve.org
  • NIST NVDCVE-2019-9740

    An issue was discovered in urllib2 in Python 2.x through 2.7.16 and urllib in Python 3.x through 3.7.3. 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 query string

    nvd.nist.gov
  • Packet Storm Securityhttp://packetstormsecurity.com/files/154927/Slackware-Security-Advisory-python-Updates.html

    Packet Storm link already published on the finding.

    packetstormsecurity.com

References

CVE-2019-9740 · ZeroDay Findings