CVE-2018-1000164

7.5 highEPSS 2.4%

gunicorn version 19.4.5 contains a CWE-113: Improper Neutralization of CRLF Sequences in HTTP Headers vulnerability in "process_headers" function in "gunicorn/http/wsgi.py" that can result in an attacker causing the server to return arbitrary HTTP headers. This vulnerability appears to have been fixed in 19.5.0.

Severity

CVSS 3.0

7.5 high

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS: 2.4% chance of exploitation in the next 30 days; higher than 83% of CVEs (scores of 2026-10-31)
CWE: CWE-93
Published: 2018-04-18
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

debian:debian_linux
gunicorn:gunicorn

Packages (OSV)

Advisory	Ecosystem	Package	Affected	Fixed in
GHSA-32pc-xphx-q4f6	PyPI	gunicorn	<19.5.0	19.5.0
PYSEC-2018-55	PyPI	gunicorn	<19.5.0	19.5.0

References

https://epadillas.github.io/2018/04/02/http-header-splitting-in-gunicorn-19.4.5
https://github.com/benoitc/gunicorn/issues/1227
https://lists.debian.org/debian-lts-announce/2018/04/msg00022.html
https://usn.ubuntu.com/4022-1/
https://www.debian.org/security/2018/dsa-4186

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