CRITICAL CWE-338
CVE-2026-61500
Rejetto HFS < 3.2.1 Session Forgery via Predictable Signing Key
Rejetto·hfs
9.8/ 10
CVSS 3.1
Critical severity
1.9%
EPSS exploit odds
Chance of exploitation in the next 30 days
Higher than 80% of all CVEs
Not listed
CISA KEV catalog
No confirmed in-the-wild exploitation on CISA's list.
Timeline
- Published
- Jul 13, 2026
- Updated
- Oct 1, 2026
- First covered
- Oct 6, 2026
- Latest story
- 1 month ago
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.
CWE-338Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)
Attack profile
Attack vectorNetwork
ComplexityLow
PrivilegesNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HAffected products
- Rejetto hfs3.0.0 to before 3.2.1