UBUNTU-CVE-2026-103503 (CVE-2026-103503)
Vulnerability from osv_ubuntu – Published: 2026-10-12 16:17 – Updated: 2026-10-28 17:50 – Source websiteImproper 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. cacerts_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. This issue affects hex: from 0.20.2 before 2.5.2.
{
"affected": [
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "erlang-hex",
"binary_version": "2.0.5-1"
}
]
},
"package": {
"ecosystem": "Ubuntu:24.04:LTS",
"name": "erlang-hex",
"purl": "pkg:deb/ubuntu/erlang-hex@2.0.5-1?arch=source\u0026distro=noble"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"2.0.5-1"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "erlang-hex",
"binary_version": "2.5.1-2"
}
]
},
"package": {
"ecosystem": "Ubuntu:26.10",
"name": "erlang-hex",
"purl": "pkg:deb/ubuntu/erlang-hex@2.5.1-2?arch=source\u0026distro=stonking"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"2.0.6-2build1",
"2.5.1-2"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "erlang-hex",
"binary_version": "2.0.6-2build1"
}
]
},
"package": {
"ecosystem": "Ubuntu:26.04:LTS",
"name": "erlang-hex",
"purl": "pkg:deb/ubuntu/erlang-hex@2.0.6-2build1?arch=source\u0026distro=resolute"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"2.0.6-2",
"2.0.6-2build1"
]
}
],
"aliases": [],
"details": "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\u0027s bundled CA store, to impersonate that host to users who set cacerts_path to a CA store that leaves that CA out. cacerts_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\u0027t contain that CA. Hostname verification still applies. This issue affects hex: from 0.20.2 before 2.5.2.",
"id": "UBUNTU-CVE-2026-103503",
"modified": "2026-10-28T17:50:29Z",
"published": "2026-10-12T16:17:00Z",
"references": [
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2026-103503"
},
{
"type": "REPORT",
"url": "https://www.cve.org/CVERecord?id=CVE-2026-103503"
},
{
"type": "REPORT",
"url": "https://cna.erlef.org/cves/CVE-2026-103503.html"
},
{
"type": "REPORT",
"url": "https://github.com/hexpm/hex/commit/5f5a2136c7cf5991b6e8a30d645ca9f8e74b0785"
},
{
"type": "REPORT",
"url": "https://github.com/hexpm/hex/commit/6232a6498015e559743bec4f4fbec9138837cec8"
},
{
"type": "REPORT",
"url": "https://github.com/hexpm/hex/commit/c9b26a46928bfcd546773571e09c1d05f4cd9fb7"
},
{
"type": "REPORT",
"url": "https://github.com/hexpm/hex/security/advisories/GHSA-rw8q-hg7m-cxgr"
},
{
"type": "REPORT",
"url": "https://osv.dev/vulnerability/EEF-CVE-2026-103503"
}
],
"related": [],
"schema_version": "1.7.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N",
"type": "CVSS_V4"
},
{
"score": "medium",
"type": "Ubuntu"
}
],
"upstream": [
"CVE-2026-103503"
]
}
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