CRLF injection in Python

1) CRLF injection

EUVDB-ID: #VU48592

Risk: Medium

CVSSv3.1: 6.3 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-26116

CWE-ID: CWE-93 - Improper Neutralization of CRLF Sequences ('CRLF Injection')

Exploit availability: No

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 in "http.client". A remote 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

Python: 3.0 - 3.8.4 rc1

External links

http://lists.opensuse.org/opensuse-security-announce/2020-11/msg00027.html
http://bugs.python.org/issue39603
http://lists.debian.org/debian-lts-announce/2020/11/msg00032.html
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/BW4GCLQISJCOEGQNIMVUZDQMIY6RR6CC/
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/HDQ2THWU4GPV4Y5H5WW5PFMSWXL2CRFD/
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/JWMAVY4T4257AZHTF2RZJKNJNSJFY24O/
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/OXI72HIHMXCQFWTULUXDG7VDA2BCYL4Y/
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/QOX7DGMMWWL6POCRYGAUCISOLR2IG3XV/
http://python-security.readthedocs.io/vuln/http-header-injection-method.html
http://security.netapp.com/advisory/ntap-20201023-0001/
http://usn.ubuntu.com/4581-1/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

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