CVE-2026-61500 Rejetto HFS < 3.2.1 Session Forgery via Predictable Signing Key
Remote attackers can forge admin sessions by predicting weak signing keys, leading to full administrative access and remote code execution.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-61500?
CVE-2026-61500 is a critical vulnerability in rejetto hfs, published on 13 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-338
Which versions are affected by CVE-2026-61500?
How do I fix CVE-2026-61500?
No fix has been published for CVE-2026-61500 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-61500 being exploited?
There is no known exploitation of CVE-2026-61500 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Sources
Also known as GHSA-xxrm-3f86-v97j.