#VU47403 CRLF injection in urllib3 - CVE-2020-26137

Vulnerability identifier: #VU47403

Vulnerability risk: Medium

CVSSv4.0: 0.6 [CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2020-26137

CWE-ID: CWE-93

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
urllib3
Other software / Other software solutions

Vendor: shazow (Andrey Petrov)

Description

The vulnerability allows a remote attacker to inject arbitrary data in server response.

The vulnerability exists due to insufficient validation of attacker-supplied data passed via the "method" parameter. A remote authenticated attacker can pass specially crafted data to the application containing CR-LF characters and modify application behavior.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

urllib3: 1.17 - 1.25.8

---

External links
https://bugs.python.org/issue39603
https://github.com/urllib3/urllib3/commit/1dd69c5c5982fae7c87a620d487c2ebf7a6b436b
https://github.com/urllib3/urllib3/pull/1800

---

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.