# CVE-2026-61500

## Summary

- **CVE ID:** CVE-2026-61500
- **Severity:** CRITICAL
- **CVSS Score:** 9.8 (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N)
- **CWE:** CWE-338
- **Published:** Jul 13, 2026
- **Last Modified:** Jul 15, 2026

## Description

Rejetto HFS 3.0.0 through 3.2.0 derives its session-cookie signing key from the non-cryptographic Math.random() generator and discloses outputs of the same generator to unauthenticated clients during login. A remote attacker can collect a small number of login responses, reconstruct the generator's state, recover the signing key, and forge a valid administrator session cookie, leading to full administrative access and remote code execution via the server_code configuration feature.

## Affected Products

- rejetto — hfs (3.0.0)

## References

- [CNA](https://github.com/rejetto/hfs/releases/tag/v3.2.1)
- [CNA](https://www.vulncheck.com/advisories/rejetto-hfs-session-forgery-via-predictable-signing-key)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.86%
- **EPSS Percentile:** 56.2

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._