← Vulnerability feed

Vulnerability record · CVE-2023-43804 · published 4 October 2023

CVE-2023-43804: Python urllib3 information exposure vulnerability

Python · Urllib3

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.

8.1 CVSS 3.1 High EPSS 1.2% · top 32.9% CWE-200 · Information exposure
8.1CVSS 3.1 base score
1.2%EPSS exploitation probability, 30 days
NoNot in CISA KEV
3Affected product versions listed by NVD
17References
17 Jun 2026Last modified by NVD

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.

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

Affected products

3 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/urllib3/urllib3/commit/01220354d389cd05474713f8c982d05c9b17aafb Patch
https://github.com/urllib3/urllib3/commit/644124ecd0b6e417c527191f866daa05a5a2056d Patch
https://github.com/urllib3/urllib3/security/advisories/GHSA-v845-jxx5-vc9f PatchVendor Advisory
https://lists.debian.org/debian-lts-announce/2023/10/msg00012.html Mailing ListThird Party Advisory
https://lists.fedoraproject.org/archives/list/[email protected]/message/5F5CUBAN5XMEBVBZPHFITBLMJ Mailing ListThird Party Advisory
https://lists.fedoraproject.org/archives/list/[email protected]/message/I3PR7C6RJ6JUBQKIJ644DMIJS Mailing ListThird Party Advisory
https://lists.fedoraproject.org/archives/list/[email protected]/message/NDAGZXYJ7H2G3SB47M453VQVN Mailing ListThird Party Advisory
https://github.com/urllib3/urllib3/commit/01220354d389cd05474713f8c982d05c9b17aafb Patch
https://github.com/urllib3/urllib3/commit/644124ecd0b6e417c527191f866daa05a5a2056d Patch
https://github.com/urllib3/urllib3/security/advisories/GHSA-v845-jxx5-vc9f PatchVendor Advisory
https://lists.debian.org/debian-lts-announce/2023/10/msg00012.html Mailing ListThird Party Advisory
https://lists.debian.org/debian-lts-announce/2024/12/msg00020.html
https://lists.fedoraproject.org/archives/list/[email protected]/message/5F5CUBAN5XMEBVBZPHFITBLMJ Mailing ListThird Party Advisory
https://lists.fedoraproject.org/archives/list/[email protected]/message/I3PR7C6RJ6JUBQKIJ644DMIJS Mailing ListThird Party Advisory
https://lists.fedoraproject.org/archives/list/[email protected]/message/NDAGZXYJ7H2G3SB47M453VQVN Mailing ListThird Party Advisory
https://security.netapp.com/advisory/ntap-20241213-0007/
https://www.vicarius.io/vsociety/posts/cve-2023-43804-urllib3-vulnerability-3

Track CVE-2023-43804 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

10.0CVE-2025-32433Erlang/OTP SSH server missing authentication allows remote code executionErlang/OTP SSH servers before OTP-27.3.3, OTP-26.2.5.11 and OTP-25.3.2.20 mishandle SSH protocol messages, letting an unauthenticated attacker execut…KEVEPSS 99%analysed10.0CVE-2025-24201Apple WebKit out-of-bounds write allows sandbox escapeCVE-2025-24201 is an out-of-bounds write in Apple's WebKit that was addressed with improved checks. Maliciously crafted web content may break out of …KEVEPSS 3.8%analysed10.0CVE-2021-44228Apache Log4j2 JNDI lookup remote code executionApache Log4j2 versions 2.0-beta9 through 2.15.0 (excluding 2.12.2, 2.12.3, and 2.3.1) do not protect against attacker-controlled LDAP and other JNDI …KEVEPSS 100%analysed9.8CVE-2026-24061GNU Inetutils telnetd argument injection allows remote auth bypasstelnetd in GNU Inetutils through 2.7 fails to sanitize the USER environment variable, so a value such as "-f root" is passed as an argument to login …KEVEPSS 99%analysed9.8CVE-2025-39682Linux kernel TLS zero-length record handling flaw on rx_listThe Linux kernel TLS receive path mishandles zero-length records that arrive from the rx_list, breaking the assumption that a record type change cann…KEVEPSS 2.9%analysed9.8CVE-2025-24813Apache Tomcat Default Servlet path equivalence enables RCE and file disclosureApache Tomcat mishandles path equivalence for names containing an internal dot, letting a remote unauthenticated attacker write files through the Def…KEVEPSS 100%analysed9.8CVE-2024-9680Mozilla Firefox and Thunderbird use-after-free in Animation timelinesA use-after-free flaw in Animation timelines allows an attacker to execute code in the content process of Firefox and Thunderbird. Mozilla reports ex…KEVEPSS 23%analysed9.8CVE-2024-4577PHP-CGI on Windows argument injection leads to remote code executionPHP-CGI on Windows can misinterpret characters in the command line passed to Win32 API functions when certain code pages are configured, due to Windo…KEVEPSS 100%analysed

Source: NIST National Vulnerability Database (record CVE-2023-43804), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.