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Fencer Intel
high 7.5

CVE-2018-1000164 json

Gunicorn contains Improper Neutralization of CRLF sequences in HTTP headers

published 8y ago modified 2mo ago also GHSA-32pc-xphx-q4f6 , PYSEC-2018-55 , EUVD-2018-0076

cvss
7.5
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.4%
EPSS 2.4% chance of exploitation in 30 days, percentile 83%
public exploits
0
none known

Summary

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.

Patch / fix

  • pypi gunicorn 19.5.0
  • gunicorn Debian 14, Debian 13, Debian 12 19.5.0-1

debian advisories DEBIAN-CVE-2018-1000164

  • gunicorn Ubuntu 16.04 LTS 19.4.5-1ubuntu1.1
  • gunicorn Ubuntu Pro 14.04 LTS 17.5-2ubuntu0.1~esm1

ubuntu advisories UBUNTU-CVE-2018-1000164

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Is CVE-2018-1000164 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2018-1000164 updated cvss 5.3

python-gunicorn: Improper neutralization of CRLF Sequences http/wsgi.py:process_headers() can allow an attacker to cause a server to return arbitrary HTTP headers

  • Red Hat Enterprise Linux 7 python-gunicorn Red Hat Storage Console 2 python-gunicorn
    affected: no fix planned “Will not fix”
  • Red Hat OpenStack Platform 12 (Pike) python-gunicorn Red Hat OpenStack Platform 13 (Queens) python-gunicorn
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

2.37% chance of exploitation in the next 30 days, higher than 83% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • epadillas.github.io https://epadillas.github.io/2018/04/02/http-header-splitting-in-gunicorn-19.4.5 referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/benoitc/gunicorn/issues/1227 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.0 7.5 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:P/A:N
GitHub 3.0 7.5 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected packages

ecosystem package affected fixed in
pypi gunicorn
<19.5.0
19.5.0

Classification

Weakness
  • CWE-93 Improper Neutralization of CRLF Sequences

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.