# CVE-2026-121730: emailflare before commit cf31f33 Missing Authorization via Inbox Compose Endpoint

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

emailflare before commit cf31f33 contains a missing authorization vulnerability in POST /api/inbox/compose that allows authenticated members to send mail as any sender address. Attackers can supply an arbitrary from field, which is passed unchecked to the Cloudflare send call, to impersonate other users or the organization to external recipients.

## 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/0xdps/emailflare/commit/cf31f33bbb4a324d5353b8a5db0312fedc19618f

## Affected products and versions

- 0xdps / emailflare (0xdps/emailflare): ≥ 0; < cf31f33bbb4a324d5353b8a5db0312fedc19618f (affected, git). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 7.1 (high); CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 6.5 (medium); CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N; source: CNA: VulnCheck

- CVSS 4.0: 7.1 (high); CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/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: 6.5 (medium); CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N; source: NVD: disclosure@vulncheck.com

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-862

## Exploit evidence

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

## References

- https://github.com/0xdps/emailflare/commit/cf31f33bbb4a324d5353b8a5db0312fedc19618f (CNA: VulnCheck; patch)

- https://github.com/0xdps/emailflare (CNA: VulnCheck; product)

- https://github.com/0xdps/emailflare/blob/d448ea205937a5e82683f89013d4c23159da5b7d/services/inbox-worker/src/routes/inbox/compose.ts (CNA: VulnCheck; technical-description)

- https://www.vulncheck.com/advisories/emailflare-before-commit-cf31f33-missing-authorization-via-inbox-compose-endpoint (CNA: VulnCheck; third-party-advisory)

- https://github.com/0xdps/emailflare (disclosure@vulncheck.com)

- https://github.com/0xdps/emailflare/blob/d448ea205937a5e82683f89013d4c23159da5b7d/services/inbox-worker/src/routes/inbox/compose.ts (disclosure@vulncheck.com)

- https://github.com/0xdps/emailflare/commit/cf31f33bbb4a324d5353b8a5db0312fedc19618f (disclosure@vulncheck.com)

- https://www.vulncheck.com/advisories/emailflare-before-commit-cf31f33-missing-authorization-via-inbox-compose-endpoint (disclosure@vulncheck.com)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-121730; retrieved 2026-11-03; source updated 2026-11-03

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-121730; retrieved 2026-11-04; source updated 2026-11-03

Revision: 8bdcf72ad775277a446180be6f73abdc88975643084b9d06644ca6b29db9f011

Canonical: https://y2.dev/cve/CVE-2026-121730

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- 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.

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