# CVE-2026-123620: Usermin through 2.570 OS Command Injection via Read Mail IMAP Folder Deletion

Status: published. Published: 2026-11-06. Updated: 2026-11-09.

Usermin through 2.570 contains an OS command injection vulnerability in the Read Mail module that allows authenticated users to execute commands through unsanitized IMAP folder names. Attackers can create a folder containing shell metacharacters via an external IMAP client, then delete it in Usermin to run commands as their system account, bypassing webmail-only restrictions.

## 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/8a45420282ff04c943f05d9241a3c55afb9bca79

## Affected products and versions

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

## Severity and prioritization

- CVSS 4.0: 7.7 (high); CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H; source: CNA: VulnCheck

- CVSS 4.0: 7.7 (high); CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/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: 7.5 (high); CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H; source: NVD: disclosure@vulncheck.com

- CISA KEV: No listing in collected sources

- EPSS: 1.38% as of 2026-11-09; percentile 72.24%

- SSVC: exploitation none; automatable no; technical impact total; source ADP: CISA-ADP

- Weaknesses: CWE-78

## Exploit evidence

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

## 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/8a45420282ff04c943f05d9241a3c55afb9bca79 (CNA: VulnCheck; patch)

- https://github.com/webmin/usermin/blob/2.570/mailbox/mailbox-lib.pl#L1031-L1040 (CNA: VulnCheck; technical-description)

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

- https://www.vulncheck.com/advisories/usermin-through-2.570-os-command-injection-via-read-mail-imap-folder-deletion (CNA: VulnCheck; third-party-advisory)

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

- https://github.com/webmin/usermin/blob/2.570/mailbox/mailbox-lib.pl#L1031-L1040 (disclosure@vulncheck.com)

- https://github.com/webmin/usermin/commit/8a45420282ff04c943f05d9241a3c55afb9bca79 (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-os-command-injection-via-read-mail-imap-folder-deletion (disclosure@vulncheck.com)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-123620; retrieved 2026-11-09; source updated 2026-11-09

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-123620; retrieved 2026-11-10; source updated 2026-11-09

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-123620; retrieved 2026-11-09; source updated Not reported

Revision: df97ffcdc97e0b059eda78dd1e6af82ee097a2d6e89ce3771f7a275642e2203a

Canonical: https://y2.dev/cve/CVE-2026-123620

## Agent and API access

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- 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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