# CVE-2026-121562: CTFd 3.1.0 before 3.8.7 Information Disclosure via /api/v1/teams Endpoint

Status: published. Published: 2026-11-03. Updated: 2026-11-09.

CTFd 3.1.0 before 3.8.7 contains an information disclosure vulnerability in the /api/v1/teams list endpoint that exposes non-public team custom field values. Unauthenticated attackers can paginate GET requests to collect hidden registration data such as emails, phone numbers, and student IDs when team mode and public visibility are enabled.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/CTFd/CTFd/commit/122c224030224ca6a04d2928280055a84bbd4850

## Affected products and versions

- CTFd / CTFd: ≥ 3.1.0; < 3.8.7 (affected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 6.9 (medium); CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 5.3 (medium); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N; source: CNA: VulnCheck

- CVSS 4.0: 6.9 (medium); CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/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; source: NVD: disclosure@vulncheck.com

- CVSS 3.1: 5.3 (medium); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N; source: NVD: disclosure@vulncheck.com

- CISA KEV: No listing in collected sources

- EPSS: 0.33% as of 2026-11-09; percentile 25.85%

- SSVC: exploitation none; automatable yes; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-863

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/CTFd/CTFd/commit/122c224030224ca6a04d2928280055a84bbd4850 (CNA: VulnCheck; patch)

- https://github.com/CTFd/CTFd (CNA: VulnCheck; product)

- https://github.com/CTFd/CTFd/blob/3.8.6/CTFd/api/v1/teams.py#L128-L131 (CNA: VulnCheck; technical-description)

- https://github.com/CTFd/CTFd/blob/3.8.6/CTFd/schemas/teams.py#L336-L363 (CNA: VulnCheck; technical-description)

- https://blog.ctfd.io/ctfd-3-8-7/ (CNA: VulnCheck; technical-description)

- https://github.com/CTFd/CTFd/releases/tag/3.8.7 (CNA: VulnCheck; technical-description, release-notes)

- https://www.vulncheck.com/advisories/ctfd-3.1.0-before-3.8.7-information-disclosure-via-api-v1-teams-endpoint (CNA: VulnCheck; third-party-advisory)

- https://blog.ctfd.io/ctfd-3-8-7/ (disclosure@vulncheck.com)

- https://github.com/CTFd/CTFd (disclosure@vulncheck.com)

- https://github.com/CTFd/CTFd/blob/3.8.6/CTFd/api/v1/teams.py#L128-L131 (disclosure@vulncheck.com)

- https://github.com/CTFd/CTFd/blob/3.8.6/CTFd/schemas/teams.py#L336-L363 (disclosure@vulncheck.com)

- https://github.com/CTFd/CTFd/commit/122c224030224ca6a04d2928280055a84bbd4850 (disclosure@vulncheck.com)

- https://github.com/CTFd/CTFd/releases/tag/3.8.7 (disclosure@vulncheck.com)

- https://www.vulncheck.com/advisories/ctfd-3.1.0-before-3.8.7-information-disclosure-via-api-v1-teams-endpoint (disclosure@vulncheck.com)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-121562; retrieved 2026-11-09; source updated 2026-11-09

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-121562; retrieved 2026-11-03; source updated 2026-11-03

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-121562; retrieved 2026-11-09; source updated Not reported

Revision: ff0f756b43b62da08e3aec2418560b8cc8d630a4c50236246b29478cf657914f

Canonical: https://y2.dev/cve/CVE-2026-121562

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- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

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