Bug 2559037

Summary: CVE-2026-103503 rust-hex: hex: Host impersonation via improper CA certificate store validation [epel-all]
Product: [Fedora] Fedora EPEL Reporter: Vipul Nair <vinair>
Component: rust-hexAssignee: Rust SIG <rust-sig>
Status: CLOSED NOTABUG QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: epel10CC: decathorpe, rust-sig
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["cb1350b1-5692-4380-916f-386fd4508c73"]}
Fixed In Version: Doc Type: ---
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2026-10-22 17:58:14 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 2449640, 2549700    

Description Vipul Nair 2026-10-22 14:21:54 UTC 
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

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 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.
Comment 1 Fabio Valentini 2026-10-22 17:58:14 UTC 
This advisory is for an issue in hex (the erlang package manager) while this package is for the hex crate (a Rust implementation of hexadecimal encoding / decoding).