{"id":"CVE-2023-27535","title":"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","summary":"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…","severity":"medium","cvss":5.9,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","cwe":["CWE-305","CWE-287"],"vendor":"haxx","product":"libcurl","affected":["libcurl >= 7.13.0, <= 7.88.1","fedora = 36","debian_linux = 10.0","active_iq_unified_manager","ontap_9","h300s_firmware","h500s_firmware","h700s_firmware","h410s_firmware","universal_forwarder >= 8.2.0, < 8.2.12","universal_forwarder >= 9.0.0, < 9.0.6","universal_forwarder = 9.1.0"],"patched":["universal_forwarder 9.0.6"],"published":"2023-03-30","updated":"2026-10-14","sourceUpdated":"2026-10-14T23:17:16.450","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2023-27535","references":[{"url":"https://hackerone.com/reports/1892780","label":"support@hackerone.com"},{"url":"https://lists.debian.org/debian-lts-announce/2023/04/msg00025.html","label":"support@hackerone.com"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/36NBD5YLJXXEDZLDGNFCERWRYJQ6LAQW/","label":"support@hackerone.com"},{"url":"https://security.gentoo.org/glsa/202310-12","label":"support@hackerone.com"},{"url":"https://security.netapp.com/advisory/ntap-20230420-0010/","label":"support@hackerone.com"},{"url":"https://hackerone.com/reports/1892780","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2023/04/msg00025.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/36NBD5YLJXXEDZLDGNFCERWRYJQ6LAQW/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.gentoo.org/glsa/202310-12","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.netapp.com/advisory/ntap-20230420-0010/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-398330.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-806742.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-943925.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"tags":["nvd","cve.org","exploit-available"],"epss":0.01607,"epssPercentile":0.75405,"ingestedAt":"2026-10-15T00:02:07.130Z","exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"no","technicalImpact":"partial","timestamp":"2025-06-03T18:24:11.710118Z"},"slug":"CVE-2023-27535","body":"## Overview\n\nAn 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.\n\n## Affected\n\n- `libcurl >= 7.13.0, <= 7.88.1`\n- `fedora = 36`\n- `debian_linux = 10.0`\n- `active_iq_unified_manager`\n- `ontap_9`\n- `h300s_firmware`\n- `h500s_firmware`\n- `h700s_firmware`\n- `h410s_firmware`\n- `universal_forwarder >= 8.2.0, < 8.2.12`\n- `universal_forwarder >= 9.0.0, < 9.0.6`\n- `universal_forwarder = 9.1.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `universal_forwarder 9.0.6`","depth":"twilight","depthScore":45,"depthScoreParts":{"impact":32.5,"likelihood":0.3,"exploitation":12,"ransomware":0},"changes":[{"seq":221968,"id":"CVE-2023-27535","ts":1792039692056,"field":"exploit_available","old":"false","new":"true"}]}