CVE-2023-27535

An authentication bypass vulnerability exists in libcurl <8.0.0 in the FTP connection reuse feature that can result in wrong credentials being used during subsequent transfers. Previously created connections are kept in a connection pool for reuse if they match the current setup. However, certain FTP settings such as CURLOPT_FTP_ACCOUNT, CURLOPT_FTP_ALTERNATIVE_TO_USER, CURLOPT_FTP_SSL_CCC, and CURLOPT_USE_SSL were not included in the configuration match checks, causing them to match too easily. This could lead to libcurl using the wrong credentials when performing a transfer, potentially allowing unauthorized access to sensitive information.

• CWE-305
• CWE-287

• https://hackerone.com/reports/1892780Exploit, Third Party Advisory
• https://lists.debian.org/debian-lts-announce/2023/04/msg00025.htmlMailing List, Third Party Advisory
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/36NBD5YLJXXEDZLDGNFCERWRYJQ6LAQW/Mailing List, Third Party Advisory
• https://security.gentoo.org/glsa/202310-12Third Party Advisory
• https://security.netapp.com/advisory/ntap-20230420-0010/Third Party Advisory
• https://hackerone.com/reports/1892780Exploit, Third Party Advisory
• https://lists.debian.org/debian-lts-announce/2023/04/msg00025.htmlMailing List, Third Party Advisory
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/36NBD5YLJXXEDZLDGNFCERWRYJQ6LAQW/Mailing List, Third Party Advisory
• https://security.gentoo.org/glsa/202310-12Third Party Advisory
• https://security.netapp.com/advisory/ntap-20230420-0010/Third Party Advisory

Published

Mar 30, 2023

Last Modified

Jun 17, 2026

Status

Modified

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
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