CVE-2026-61500 (GCVE-0-2026-61500)

Vulnerability from cvelistv5 – Published: 2026-07-13 17:21 – Updated: 2026-10-01 15:20 X_Open Source
VLAI Previdian
Title
Rejetto HFS < 3.2.1 Session Forgery via Predictable Signing Key
Summary
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.
Severity
9.3 (Critical)
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
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
SSVC
Exploitation: none Automatable: yes Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-07-15 14:14 UTC
CWE
  • CWE-338 - Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)
Assigner
VulnCheck CNA under the mitre root
CNA scorecard B 84/100 over 6903 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
rejetto hfs Affected: 3.0.0 , < 3.2.1 (semver)
    cpe:2.3:a:rejetto:http_file_server:*:*:*:*:*:*:*:*
Create a notification for this product.
Date Public
2026-07-13 00:00
Credits
Zach Hanley (@hacks_zach) of Horizon3.ai, in collaboration with Claude and Anthropic Research
Previdian
Known Exploited Vulnerability - GCVE BCP-07 Compliant
KEV entry ID: 5fbc5d1d-e4ac-4880-b93f-0ecc0c64d0ae

Vulnerability ID: CVE-2026-61500

Status: Confirmed

Status Updated: 2026-10-05 08:32 UTC

Exploited: Yes

Timestamps
First Seen: 2026-10-05
Asserted: 2026-10-05
Scope
Notes: Rejetto HFS < 3.2.1 Session Forgery via Predictable Signing Key | Affected: Rejetto / hfs | CVSS: 9.3 (CRITICAL) | EPSS: 0.00987 | Used in malware: unknown | Not yet in CISA KEV: True
Evidence

Type: Public Report

Signal: Successful Exploitation

Confidence: 70%

Source: previdian

Details
Feed Previdian (previdian.com)
Title Rejetto HFS < 3.2.1 Session Forgery via Predictable Signing Key
Cve Id CVE-2026-61500
Vendor Rejetto
Ghsa Id None
Product hfs
Added Date 2026-10-05T08:32:18.906Z
Cvss Score 9.3
Epss Score 0.00987
Previous Ids
Cvss Severity CRITICAL
Virtual Patch False
Cvss Estimated False
Epss Percentile 0.61116
Used In Malware unknown
Vulnerability Id CVE-2026-61500
Ahead Of Cisa Kev None
Not Yet In Cisa Kev True
References
Created: 2026-10-06 09:00 UTC | Updated: 2026-10-06 09:00 UTC
Show details on NVD website
To clipboard 

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