CVE-2023-43804

Name: CVE-2023-43804
Creator: NVD / NIST
Published: 2023-10-04T17:15:10.163+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.1/10EPSS 1.21%

Last modified Jun 17, 2026

CVE-2023-43804 is a high-severity vulnerability rated 8.1/10 on the CVSS scale. urllib3 is a user-friendly HTTP client library for Python. urllib3 doesn't treat the `Cookie` HTTP header special or provide any helpers for managing cookies over HTTP, that is the responsibility of the user. EPSS estimates a 1.21% chance of exploitation in the next 30 days.

Description

urllib3 is a user-friendly HTTP client library for Python. urllib3 doesn't treat the `Cookie` HTTP header special or provide any helpers for managing cookies over HTTP, that is the responsibility of the user. However, it is possible for a user to specify a `Cookie` header and unknowingly leak information via HTTP redirects to a different origin if that user doesn't disable redirects explicitly. This issue has been patched in urllib3 version 1.26.17 or 2.0.5.

Metrics

CVSS 3.1

8.1/10

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

EPSS Probability

1.21%

64.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-200

Affected Software

Vendor	Product	Versions
Python	Urllib3	< 1.26.17
Python	Urllib3	>= 2.0.0, < 2.0.6
Debian	Debian Linux	10.0
Fedoraproject	Fedora	37
Fedoraproject	Fedora	38
Fedoraproject	Fedora	39

References

https://github.com/urllib3/urllib3/commit/01220354d389cd05474713f8c982d05c9b17aafbPatch
https://github.com/urllib3/urllib3/commit/644124ecd0b6e417c527191f866daa05a5a2056dPatch
https://github.com/urllib3/urllib3/security/advisories/GHSA-v845-jxx5-vc9fPatch, Vendor Advisory
https://lists.debian.org/debian-lts-announce/2023/10/msg00012.htmlMailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/5F5CUBAN5XMEBVBZPHFITBLMJV5FIJJ5/Mailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/I3PR7C6RJ6JUBQKIJ644DMIJSUP36VDY/Mailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NDAGZXYJ7H2G3SB47M453VQVNAWKAEJJ/Mailing List, Third Party Advisory
https://github.com/urllib3/urllib3/commit/01220354d389cd05474713f8c982d05c9b17aafbPatch
https://github.com/urllib3/urllib3/commit/644124ecd0b6e417c527191f866daa05a5a2056dPatch
https://github.com/urllib3/urllib3/security/advisories/GHSA-v845-jxx5-vc9fPatch, Vendor Advisory
https://lists.debian.org/debian-lts-announce/2023/10/msg00012.htmlMailing List, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2024/12/msg00020.html
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/5F5CUBAN5XMEBVBZPHFITBLMJV5FIJJ5/Mailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/I3PR7C6RJ6JUBQKIJ644DMIJSUP36VDY/Mailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NDAGZXYJ7H2G3SB47M453VQVNAWKAEJJ/Mailing List, Third Party Advisory
https://security.netapp.com/advisory/ntap-20241213-0007/
https://www.vicarius.io/vsociety/posts/cve-2023-43804-urllib3-vulnerability-3

Timeline

Published: Oct 4, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-43804?

How severe is CVE-2023-43804?

CVE-2023-43804 has a CVSS score of 8.1/10 (HIGH severity). The EPSS model estimates a 1.21% probability of exploitation in the next 30 days.

How do I fix CVE-2023-43804?

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-2023-43804?

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

Scan your code now

Source: NVD / NIST