Patchfirst
CVE-2026-61500 Public exploit Critical · 9.8 EPSS 1.9%

Rejetto HFS < 3.2.1 Session Forgery via Predictable Signing Key

rejetto · hfs

Summary

The flaw is a predictable session-signing key in Rejetto HFS, affecting versions 3.0.0 through 3.2.0, where the key is derived from the non-cryptographic Math.random() generator whose outputs are exposed to unauthenticated clients during login. An unauthenticated remote attacker needing no user interaction or prior authentication can collect a few login responses, reconstruct the generator's state to recover the signing key, forge an administrator session cookie, and thereby gain full administrative access and remote code execution through the server_code configuration feature.

Official description · CVE.org

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.

Breakdown
72.8 / 100
Exploited
Yes, in VulnCheck KEV
Reports
0
Tactics
0/15

First seen exploited 3 months after disclosure. Public exploit code (PoC-in-GitHub) appeared 2 months after disclosure.

  1. Disclosedday 0
  2. Public exploit codePoC-in-GitHub+2 mo
  3. First seen exploitedVulnCheck KEV evidence+3 mo

techniques

No techniques linked

No ATT&CK techniques are linked to this CVE yet. MITRE CTID has not mapped it, and no report passage in the corpus ties it to a technique.

What security researchers reported

Not named in any threat report yet

References

2 links, grouped by NVD tag
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