# CVE-2026-123622: Usermin through 2.570 XSS via mailbox detach.cgi type Parameter

Status: published. Published: 2026-11-06. Updated: 2026-11-11.

Usermin through 2.570 contains a cross-site scripting vulnerability in mailbox/detach.cgi that allows remote attackers to execute script by supplying an arbitrary type parameter that bypasses JavaScript filtering. Attackers can email an HTML attachment containing script and lure recipients to a detach.cgi link with type=text/html to run script in the victim's authenticated Usermin session.

## 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/webmin/usermin/commit/c5c43b9ad04a60809ac2eb271bf8f3d0fec2e46a

## Affected products and versions

- webmin / usermin (webmin/usermin): ≥ 0; ≤ 2.570 (affected, custom). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 5.1 (medium); CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 6.1 (medium); CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N; source: CNA: VulnCheck

- CVSS 4.0: 5.1 (medium); CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/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: 6.1 (medium); CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N; source: NVD: disclosure@vulncheck.com

- CISA KEV: No listing in collected sources

- EPSS: 0.26% as of 2026-11-10; percentile 17.76%

- SSVC: exploitation poc; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-79

## Exploit evidence

- exploit: https://hackmd.io/@leediay/H144QKY6zl (ADP: CISA-ADP)

## References

- https://github.com/webmin/usermin/issues/142 (CNA: VulnCheck; issue-tracking)

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

- https://github.com/webmin/usermin/commit/c5c43b9ad04a60809ac2eb271bf8f3d0fec2e46a (CNA: VulnCheck; patch)

- https://github.com/webmin/usermin/blob/2.570/mailbox/detach.cgi#L80-L83 (CNA: VulnCheck; technical-description)

- https://hackmd.io/@leediay/H144QKY6zl (CNA: VulnCheck; technical-description)

- https://www.vulncheck.com/advisories/usermin-through-2.570-xss-via-mailbox-detach-cgi-type-parameter (CNA: VulnCheck; third-party-advisory)

- https://hackmd.io/@leediay/H144QKY6zl (ADP: CISA-ADP; exploit)

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

- https://github.com/webmin/usermin/blob/2.570/mailbox/detach.cgi#L80-L83 (disclosure@vulncheck.com)

- https://github.com/webmin/usermin/commit/c5c43b9ad04a60809ac2eb271bf8f3d0fec2e46a (disclosure@vulncheck.com)

- https://github.com/webmin/usermin/issues/142 (disclosure@vulncheck.com)

- https://hackmd.io/@leediay/H144QKY6zl (disclosure@vulncheck.com)

- https://www.vulncheck.com/advisories/usermin-through-2.570-xss-via-mailbox-detach-cgi-type-parameter (disclosure@vulncheck.com)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-123622; retrieved 2026-11-11; source updated 2026-11-11

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-123622; retrieved 2026-11-06; source updated 2026-11-06

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-123622; retrieved 2026-11-11; source updated Not reported

Revision: c76950615e169b201b64de68fc4c027e83f32a00e7fcae5caeee9fcf2fe1a8d7

Canonical: https://y2.dev/cve/CVE-2026-123622

## 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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