# CVE-2026-26248: CVE-2026-26248

Status: published. Published: 2026-11-10. Updated: 2026-11-11.

A improper neutralization of input during web page generation ('cross-site scripting') vulnerability in Fortinet FortiSandbox 5.0.0 through 5.0.5, FortiSandbox 4.4.0 through 4.4.8, FortiSandbox 4.2 all versions, FortiSandbox Cloud 5.0.4 through 5.0.5, FortiSandbox PaaS 5.0.4 through 5.0.5 may allow an unauthenticated attacker to perform an XSS attack via social engineering and crafted HTTP requests.

## Remediation

- fix: Upgrade to FortiSandbox version 5.2.0 or above
Upgrade to FortiSandbox version 5.0.6 or above
Upgrade to FortiSandbox version 4.4.9 or above
Upgrade to FortiSandbox PaaS version 5.2.0 or above
Upgrade to FortiSandbox PaaS version 5.0.6 or above
Upgrade to FortiSandbox Cloud version 5.0.6 or above (source: CNA: fortinet)

## Affected products and versions

- Fortinet / FortiSandbox: ≥ 5.0.0; ≤ 5.0.5 (affected, semver); ≥ 4.4.0; ≤ 4.4.8 (affected, semver); ≥ 4.2.1; ≤ 4.2.8 (affected, semver). Source: CNA: fortinet
- Fortinet / FortiSandbox Cloud: ≥ 5.0.4; ≤ 5.0.5 (affected, semver). Source: CNA: fortinet
- Fortinet / FortiSandbox PaaS: ≥ 5.0.4; ≤ 5.0.5 (affected, semver). Source: CNA: fortinet

## Severity and prioritization

- CVSS 3.1: 7.9 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C; source: CNA: fortinet

- CVSS 3.1: 8.8 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H; source: NVD: psirt@fortinet.com

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-79

## Exploit evidence

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

## References

- https://fortiguard.fortinet.com/psirt/FG-IR-26-142 (CNA: fortinet)

- https://fortiguard.fortinet.com/psirt/FG-IR-26-142 (psirt@fortinet.com)

## Provenance

- CNA: fortinet: https://www.cve.org/CVERecord?id=CVE-2026-26248; retrieved 2026-11-11; source updated 2026-11-11

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-26248; retrieved 2026-11-11; source updated 2026-11-10

Revision: 396fba6ee21cdca2ccf6d4e64ea5f0a2af0e7e8957821d501c47025b319febfd

Canonical: https://y2.dev/cve/CVE-2026-26248

## 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.

Collected public records only. Check source status for coverage and freshness.