{"id":"CVE-2026-103503","title":"Improper Certificate Validation vulnerability in hexpm hex allows an attacker who can intercept HTTPS connections, and holds a certificate for a Hex host issued by a CA in Hex's bundled CA store, to impersonate that host to users who set…","summary":"Improper Certificate Validation vulnerability in hexpm hex allows an attacker who can intercept HTTPS connections, and holds a certificate for a Hex host issued by a CA in Hex's bundled CA store, to impersonate that host to users who set…","severity":"none","cwe":["CWE-295"],"published":"2026-10-12","updated":"2026-10-12","sourceUpdated":"2026-10-12T16:17:02.427","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-103503","references":[{"url":"https://cna.erlef.org/cves/CVE-2026-103503.html","label":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"},{"url":"https://github.com/hexpm/hex/commit/5f5a2136c7cf5991b6e8a30d645ca9f8e74b0785","label":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"},{"url":"https://github.com/hexpm/hex/commit/6232a6498015e559743bec4f4fbec9138837cec8","label":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"},{"url":"https://github.com/hexpm/hex/commit/c9b26a46928bfcd546773571e09c1d05f4cd9fb7","label":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"},{"url":"https://github.com/hexpm/hex/security/advisories/GHSA-rw8q-hg7m-cxgr","label":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-103503","label":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"}],"tags":["nvd"],"ingestedAt":"2026-10-12T16:57:59.908Z","slug":"CVE-2026-103503","body":"## Overview\n\nImproper Certificate Validation vulnerability in hexpm hex allows an attacker who can intercept HTTPS connections, and holds a certificate for a Hex host issued by a CA in Hex's bundled CA store, to impersonate that host to users who set cacerts_path to a CA store that leaves that CA out.\n\ncacerts_path (HEX_CACERTS_PATH) is documented as the path to the CA certificate store, used instead of the CA bundle that ships with Hex. Hex.HTTP.SSL.ssl_opts/1 passes the configured store as the cacerts option, but builds the partial_chain callback from the bundled store whether cacerts_path is set or not. Hex.HTTP.SSL.partial_chain/2 accepts a server chain when any certificate in it has the same public key as a bundled CA certificate, so a chain that leads to a bundled CA passes verification although the configured store doesn't contain that CA. Hostname verification still applies.\n\nThis issue affects hex: from 0.20.2 before 2.5.2.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}