Medium severity · published Jul 13, 2026
CVE-2026-61503
Rejetto HFS < 3.2.1 Username Enumeration via Login Response Differences
5.3
CVSS
0.4%
EPSS
No
On KEV
Description
Rejetto HFS 3.0.0 through 3.2.0 returns observably different responses from its login endpoint depending on whether the submitted username exists. A remote unauthenticated attacker can use this to confirm valid account names, including the default admin account, facilitating password-guessing and session-forgery attacks.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 38% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
HF
hfs · rejetto
3.0.0 before 3.2.1 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-61503
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-61503
release-notes
https://github.com/rejetto/hfs/releases/tag/v3.2.1
third-party-advisory
https://www.vulncheck.com/advisories/rejetto-hfs-username-enumeration-via-login-response-differences
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