CVE-2026-86698: hexpm Insufficient Session Expiration

Vulnerability summary

CVE-2026-86698 is a low (CVSS 2.3) Insufficient Session Expiration vulnerability in hexpm. EPSS estimates a 0.43% chance of exploitation in the next 30 days, higher than 35.5% of scored vulnerabilities.

Timeline

1. 22-09-2026
   PublishedVulnerability first disclosed.
2. 22-09-2026
   Last modifiedVulnerability information updated.

Description

Insufficient Session Expiration vulnerability in OAuth token issuance in hexpm hexpm allows a user whose organization membership or session has ended to keep reading the organization's private packages and their documentation tarballs via a retained refresh token. generate_refresh_token/4 in lib/hexpm/oauth/jwt.ex signs the refresh token with the same iss, aud and scope claims as the access token, so it carries the same repository:<org> scopes. The CDN service that serves private repositories verifies the signature and time claims and then authorizes from the scope claim, with no database lookup and no way to tell the two token kinds apart. Removing a member or revoking a session therefore takes effect at the CDN only when the 30 day refresh token expires, instead of after the 30 minute access token lifetime. Access is read-only and limited to organizations the account belonged to when the token was granted. This issue affects hex.pm: from 2025-10-10 before 2026-09-22.

• CWE-613Insufficient Session ExpirationAccording to WASC, "Insufficient Session Expiration is when a web site permits an attacker to reuse old session credentials or session IDs for authorization."