What is CVE-2026-61500?

CVE-2026-61500 is a critical-severity vulnerability in Rejetto Hfs, classified under Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG). CVSS score: 9.8/10. Published 2026-07-13.

How severe is CVE-2026-61500?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Vulnerability in Rejetto Hfs

CVE-2026-61500

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.

EPSS: 0.009 (55.7th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Rejetto Hfs — versions 3.0.0

Weakness classification (CWE)

CWE-338 — Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)

References

disclosure@vulncheck.com (release-notes, patch)
disclosure@vulncheck.com (third-party-advisory)

Frequently asked questions

What is CVE-2026-61500?: CVE-2026-61500 is a critical-severity vulnerability in Rejetto Hfs, classified under Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG). CVSS score: 9.8/10. Published 2026-07-13.
How severe is CVE-2026-61500?: Critical severity. CVSS v3 base score is 9.8 out of 10.