by Kastro
Paper/Archive/CVE-2026-61500

CVE-2026-61500

rejetto hfs — Rejetto HFS < 3.2.1 Session Forgery via Predictable Signing Key

EPSS 2%CVSS 9.8
critical.is priorityof 100
45
CVSS 9.8 (CNA)9.8 / 10 × 3029.4Not in CISA KEV+300.0EPSS percentile 79.7.797 × 2015.9No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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

ProductAffectedFixed inSource
hfs3.0.0 – < 3.2.13.2.1CNA

Scores by source

VulnCheck (CNA)9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
VulnCheck (CNA)9.3CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

patchgithub.com/rejetto/hfs/releases/tag/v3.2.1writeupvulncheck.com/advisories/rejetto-hfs-session-forgery-via-predictable-signing-key