CVE-2026-61500

CRITICAL

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.

CVSS v3.1 Score

9.8
CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Published: 7/13/2026Modified: 7/15/2026

Related Intelligence (3)

CRITICALVulnerability

Rejetto HFS servers now actively scanned for critical RCE flaw

Hackers are actively scanning for a Rejetto HFS weak signing key vulnerability, tracked as CVE-2026-61500, that allows session forgery, account takeover, and remote code execution (RCE). [...]

CVE-2026-61500
BleepingComputer
LOWVulnerability

Exploitation Hits Rejetto HFS Vulnerability Discovered by AI

CVE-2026-61500 allows attackers to recover the session-cookie signing key and gain administrative access and RCE. The post Exploitation Hits Rejetto HFS Vulnerability Discovered by AI appeared first on SecurityWeek .

CVE-2026-61500
SecurityWeek
CRITICALVulnerability

Attackers Target Rejetto HFS Flaw That Enables Admin Session Forgery and RCE

A critical security flaw impacting Rejetto HTTP File Server (HFS) is witnessing active exploitation attempts, according to VulnCheck. The vulnerability in question is CVE-2026-61500 (CVSS score: 9.3), a case of session forgery stemming from the use of a weak pseudo-random number generator (PRNG) that can lead to a predictable key, which an attacker can then use to gain unauthorized access and

CVE-2026-61500
The Hacker News

References (2)

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