Vulnerability · Published Sep 22, 2026 · Assigned by EEF
CVE-2026-86698Refresh tokens accepted as private repository credentials at the CDN
Low 2.3
In plain English
A low-severity security flaw in hexpm from hexpm. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 37% of all known vulnerabilities).
Official 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.
Affected products (as reported)
Weakness: CWE-613 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N
References
- Refresh tokens are accepted as private repository credentials at the CDN vendor-advisory, related
- EEF CNA record for CVE-2026-86698 related
- OSV record EEF-CVE-2026-86698 related
- Introducing commit 650faa0 in hexpm/hexpm related
- Fix commit db58cf3 in hexpm/hexpm patch