CVE-2020-26137

Name: CVE-2020-26137
Creator: NVD / NIST
Published: 2020-09-30T18:15:26.773+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 2.23%

Last modified Jun 17, 2026

CVE-2020-26137 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. urllib3 before 1.25.9 allows CRLF injection if the attacker controls the HTTP request method, as demonstrated by inserting CR and LF control characters in the first argument of putrequest(). NOTE: this is similar to CVE-2020-26116.. EPSS estimates a 2.23% chance of exploitation in the next 30 days.

Description

urllib3 before 1.25.9 allows CRLF injection if the attacker controls the HTTP request method, as demonstrated by inserting CR and LF control characters in the first argument of putrequest(). NOTE: this is similar to CVE-2020-26116.

Metrics

CVSS 3.1

6.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

EPSS Probability

2.23%

80.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-74

Affected Software

Vendor	Product	Versions
Python	Urllib3	< 1.25.9
Canonical	Ubuntu Linux	16.04
Canonical	Ubuntu Linux	18.04
Canonical	Ubuntu Linux	20.04
Debian	Debian Linux	9.0
Oracle	Communications Cloud Native Core Network Function Cloud Native Environment	22.2.0
Oracle	Zfs Storage Appliance Kit	8.8

References

https://bugs.python.org/issue39603Issue Tracking, Vendor Advisory
https://github.com/urllib3/urllib3/commit/1dd69c5c5982fae7c87a620d487c2ebf7a6b436bPatch, Third Party Advisory
https://github.com/urllib3/urllib3/pull/1800Patch, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/06/msg00015.htmlMailing List, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2023/10/msg00012.html
https://usn.ubuntu.com/4570-1/Third Party Advisory
https://www.oracle.com/security-alerts/cpujul2022.htmlPatch, Third Party Advisory
https://www.oracle.com/security-alerts/cpuoct2021.htmlPatch, Third Party Advisory
https://bugs.python.org/issue39603Issue Tracking, Vendor Advisory
https://github.com/urllib3/urllib3/commit/1dd69c5c5982fae7c87a620d487c2ebf7a6b436bPatch, Third Party Advisory
https://github.com/urllib3/urllib3/pull/1800Patch, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/06/msg00015.htmlMailing List, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2023/10/msg00012.html
https://usn.ubuntu.com/4570-1/Third Party Advisory
https://www.oracle.com/security-alerts/cpujul2022.htmlPatch, Third Party Advisory
https://www.oracle.com/security-alerts/cpuoct2021.htmlPatch, Third Party Advisory

Timeline

Published: Sep 30, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-26137?

How severe is CVE-2020-26137?

CVE-2020-26137 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 2.23% probability of exploitation in the next 30 days.

How do I fix CVE-2020-26137?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-26137?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST