CVE-2023-27535: 
MySQL vulnerability analysis and mitigation

An authentication bypass vulnerability (CVE-2023-27535) was discovered in libcurl versions prior to 8.0.0. The vulnerability exists in the FTP connection reuse feature that can result in wrong credentials being used during subsequent transfers. The issue was reported by Harry Sintonen on March 5, 2023, and was fixed with the release of curl 8.0.0 on March 20, 2023 (Curl Advisory).

The vulnerability stems from libcurl's connection pooling mechanism where previously created connections are kept for reuse if they match the current setup. However, several FTP settings were omitted from the configuration match checks, making them match too easily. The affected settings include CURLOPTFTPACCOUNT, CURLOPTFTPALTERNATIVETOUSER, CURLOPTFTPSSLCCC, and CURLOPTUSE_SSL. The vulnerability has been assigned a CVSS v3.1 base score of 5.9 (Medium) with the vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N (NVD, NetApp Advisory).

When exploited, this vulnerability could lead to libcurl using incorrect credentials when performing transfers, potentially allowing unauthorized access to sensitive information. The impact is primarily related to confidentiality breaches, as indicated by the CVSS score showing high confidentiality impact but no integrity or availability impact (NetApp Advisory).

The primary mitigation is to upgrade curl to version 8.0.0 or later. The fix was implemented in commit 8f4608468b890dc. For systems that cannot be immediately upgraded, there are no known workarounds available (Curl Advisory, Debian Advisory).

Multiple vendors and distributions have released security advisories and patches for this vulnerability, including Debian, Fedora, Gentoo, and NetApp. The vulnerability was assigned a bounty of 2400 USD through the curl bug bounty program (Curl Advisory, Gentoo Advisory).