# CVE-2026-121526: CVE-2026-121526

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

A url redirection to untrusted site ('open redirect') vulnerability in Fortinet FortiAuthenticator 8.0.0 through 8.0.3, FortiAuthenticator 6.6.0 through 6.6.10 may allow an unauthenticated attacker to perform an open redirect attack via crafted HTTP requests.

## Remediation

- fix: Upgrade to FortiAuthenticator version 8.0.4 or above
Upgrade to FortiAuthenticator version 6.6.11 or above (source: CNA: fortinet)

## Affected products and versions

- Fortinet / FortiAuthenticator: ≥ 8.0.0; ≤ 8.0.3 (affected, semver); ≥ 6.6.0; ≤ 6.6.10 (affected, semver); ≥ 6.5.0; ≤ 6.5.7 (affected, semver). Source: CNA: fortinet

## Severity and prioritization

- CVSS 3.1: 5.8 (medium); CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N/E:P/RL:O/RC:C; source: CNA: fortinet

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-601

## Exploit evidence

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

## References

- https://fortiguard.fortinet.com/psirt/FG-IR-26-191 (CNA: fortinet)

## Provenance

- CNA: fortinet: https://www.cve.org/CVERecord?id=CVE-2026-121526; retrieved 2026-11-11; source updated 2026-11-11

Revision: 2b50be9d8ae43a299ea9bc1cd18cdd5dce9bc7cb0e278c7cecff468250cff5d7

Canonical: https://y2.dev/cve/CVE-2026-121526

## Agent and API access

Public CVE pages, Markdown, and JSON are free to read without an account or API key.

- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search, filters, sort, and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

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

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