Explicit organization scopes survive token refresh after membership ends
Insufficient Session Expiration vulnerability in the OAuth token refresh grant in hexpm hexpm allows a user removed from an organization to keep reading its private packages. expand_repositories_scope/3 in lib/hexpm/permissions.ex only rewrites the literal repositories scope, so an explicitly granted repository:<org> or docs:<org> scope passes through it untouched. The refresh grant re-derives a new token from the stored granted_scopes, which holds that expanded form, so every refresh reproduces the organization scope without revisiting membership. Because both CDN edges authorize repository access from the token claim without querying the database, an account removed from an organization retains read access for as long as it keeps refreshing, bounded by the 30 day refresh token lifetime rather than the 30 minute access token lifetime. This issue affects hex.pm: from 2025-10-10 before 2026-08-24.
- Published
- Aug 24, 2026
- Updated
- Sep 1, 2026
- EPSS
- 0.4% · 35th percentile
- CWE
- CWE-613
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Report tools
Action score
9
Monitor
Low priority for now.
- CVSS
- 9 / 40 · 2.3 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.4%
CISA SSVC decision
- Exploitation
- proof of concept
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · EEF
- 2.3
- NVD has not scored this yet; the score shown is the CNA’s.
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
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpAffected systems
—
Versions reported by the vendor
Affected version ranges reported by the assigning authority (EEF). Independent of NVD's CPE analysis and usually ahead of it.
hexpm hexpm
- 2025-10-10 and later · before 2026-08-24affected · date
- 650faa03af511e74c1b3b49ec12d35666b6984c4 and later · before 50cffd206490c49c92d7b63c8505949682abedb0affected · git
Same product
hexpm: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-75542OAuth token exchange grants repository scopes for organizations the principal cannot access33Monitor
- CVE-2026-86698Refresh tokens accepted as private repository credentials at the CDN9Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| hexpm hexpm | 2026-08-24 | Vendor (CNA) |
| hexpm hexpm | 50cffd206490c49c92d7b63c8505949682abedb0 | Vendor (CNA) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
- Eric Meadows-Jönssonfinder
- Jonatan Männchen / EEFcoordinator
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2026-8669829 days apartRefresh tokens accepted as private repository credentials at the CDN9Monitor
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
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Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- Integrity
- Availability
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- X
Weakness class (CWE)
CWE-613 · Insufficient Session ExpirationCVSS 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- cna.erlef.org/cves/CVE-2026-75554.html
- github.com/hexpm/hexpm/commit/50cffd206490c49c92d7b63c8505949682abedb0
- github.com/hexpm/hexpm/security/advisories/GHSA-24ww-j3f4-p49c
- osv.dev/vulnerability/EEF-CVE-2026-75554
Vendor advisories and official records. Exploit/PoC links are deliberately left out.