Low severity · published Aug 25, 2026
CVE-2026-80199
Kimai before 2.54.0 Username Enumeration via Timing Oracle
3.7
CVSS
0.3%
EPSS
No
On KEV
Description
Kimai before 2.54.0 contains a timing oracle vulnerability in TokenAuthenticator that allows unauthenticated attackers to enumerate valid usernames via X-AUTH-USER header. Attackers can measure response time differences when the password hasher runs only for existing users, enabling username enumeration with no login throttling protection.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 24% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
KI
kimai · kimai
before 2.54.0 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-80199
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-80199
vendor-advisory
https://github.com/kimai/kimai/security/advisories/GHSA-jrc6-fmhw-fpq2
third-party-advisory
https://www.vulncheck.com/advisories/kimai-before-2.54.0-username-enumeration-via-timing-oracle
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