Vulnerability in Python

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. 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.

Vulnerability class: CRLF Injection

EPSS: 0.055 (92.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

  • cve@mitre.org (VDB Entry, Third Party Advisory, vdb-entry, x_refsource_BID)
  • cve@mitre.org (x_refsource_FEDORA, vendor-advisory)
  • cve@mitre.org (x_refsource_REDHAT, vendor-advisory, Third Party Advisory)
  • cve@mitre.org (x_refsource_FEDORA, vendor-advisory)
  • cve@mitre.org (mailing-list, x_refsource_MLIST, Mailing List, Third Party Advisory)
  • cve@mitre.org (mailing-list, x_refsource_MLIST, Mailing List, Third Party Advisory)
  • cve@mitre.org (mailing-list, x_refsource_MLIST, Mailing List, Third Party Advisory)
  • cve@mitre.org (x_refsource_FEDORA, vendor-advisory)
  • cve@mitre.org (x_refsource_FEDORA, vendor-advisory)
  • cve@mitre.org (x_refsource_REDHAT, vendor-advisory, Third Party Advisory)

Frequently asked questions

What is CVE-2019-9740?
CVE-2019-9740 is a medium-severity vulnerability in Python, classified under CRLF Injection. CVSS score: 6.1/10. Published 2019-03-13.
How severe is CVE-2019-9740?
Medium severity. CVSS v3 base score is 6.1 out of 10.
Is CVE-2019-9740 known to be exploited?
3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.