# CVE-2026-126571: Padloc 4.0.0 before 4.3.1 Email MFA Code Brute Force via retrieveMFAToken

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

Padloc 4.0.0 before 4.3.1 contains an authentication bypass vulnerability in the legacy retrieveMFAToken handler that never counts wrong email verification codes toward the attempt limit. Unauthenticated attackers knowing a victim's email can brute force the 6-digit code to obtain verification tokens usable in signup, login and account recovery flows.

## 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/padloc/padloc/commit/26f292515fe623826070454872f9cee08b756544

## Affected products and versions

- padloc / padloc (padloc/padloc): ≥ 4.0.0; < 4.3.1 (affected, semver); 4.3.1 (unaffected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 6.3 (medium); CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 4.8 (medium); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N; source: CNA: VulnCheck

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-307

## Exploit evidence

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

## References

- https://github.com/padloc/padloc/security/advisories/GHSA-3mq5-m2qg-fqhq (CNA: VulnCheck; vendor-advisory)

- https://github.com/padloc/padloc/commit/26f292515fe623826070454872f9cee08b756544 (CNA: VulnCheck; patch)

- https://github.com/padloc/padloc/blob/v4.3.0/packages/core/src/v3-compat.ts#L191-L210 (CNA: VulnCheck; technical-description)

- https://www.vulncheck.com/advisories/padloc-4.0.0-before-4.3.1-email-mfa-code-brute-force-via-retrievemfatoken (CNA: VulnCheck; third-party-advisory)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-126571; retrieved 2026-11-11; source updated 2026-11-11

Revision: c90242c753016889f005e97c31f558af4b4fec54cc3227bce44260e7cbc1f31c

Canonical: https://y2.dev/cve/CVE-2026-126571

## 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.