PatchSiren cyber security CVE debrief
CVE-2026-80199 kimai CVE debrief
AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-08-26T05:18:27.530Z and has not been modified since then. The Kimai application, prior to version 2.54.0, contains a timing oracle vulnerability in the TokenAuthenticator. This vulnerability allows unauthenticated attackers to enumerate valid usernames by measuring response time differences when the password hasher runs only for existing users. System administrators and security professionals responsible for Kimai installations, particularly those exposed to untrusted networks or users, should be aware of this vulnerability and take appropriate defensive measures. Medium-priority defensive actions are recommended due to potential for username enumeration. Evidence from official CVE and NVD sources indicates a timing oracle vulnerability in Kimai's TokenAuthenticator, allowing unauthenticated attackers to enumerate valid usernames. Defensive measures should focus on limiting exposure and monitoring for suspicious activity.
- Vendor
- kimai
- Product
- Unknown
- CVSS
- MEDIUM 6.3
- CISA KEV
- Not listed in stored evidence
- Original CVE published
- 2026-08-26
- Original CVE updated
- 2026-08-31
- Advisory published
- 2026-08-26
- Advisory updated
- 2026-08-31
Who should care
System administrators and security professionals responsible for Kimai installations, particularly those exposed to untrusted networks or users, should be aware of this vulnerability and take appropriate defensive measures.
Technical summary
The Kimai application, prior to version 2.54.0, contains a timing oracle vulnerability in the TokenAuthenticator. This vulnerability allows unauthenticated attackers to enumerate valid usernames by measuring response time differences when the password hasher runs only for existing users. The vulnerability is characterized by the following: CVSS Score: 6.3, CVSS Severity: MEDIUM, CVSS Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. The CWE associated with this vulnerability is CWE-208.
Defensive priority
Medium-priority defensive actions recommended due to potential for username enumeration.
Recommended defensive actions
- Implement Web Application Firewall (WAF) rules to detect and prevent suspicious X-AUTH-USER header usage
- Enforce rate limiting on authentication attempts to slow down enumeration efforts
- Monitor system logs for unusual response times or patterns indicative of enumeration attempts
- Consider implementing additional authentication factors to reduce reliance on username/password combinations
- Upgrade to Kimai version 2.54.0 or later when available
Evidence notes
Evidence from official CVE and NVD sources indicates a timing oracle vulnerability in Kimai's TokenAuthenticator, allowing unauthenticated attackers to enumerate valid usernames. Defensive measures should focus on limiting exposure and monitoring for suspicious activity.
Sources and references
Verified primary and authoritative sources
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CVE-2026-80199 CVE Program record
Publisher, destination, and source semantics verified
URL: https://www.cve.org/CVERecord?id=CVE-2026-80199
CVE Program - Official CVE Program record with source-provided CVE metadata.
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CVE-2026-80199 NVD vulnerability detail
Publisher, destination, and source semantics verified
URL: https://nvd.nist.gov/vuln/detail/CVE-2026-80199
NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.
Supplemental references
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Source reference
Unverified legacy reference
URL: https://github.com/kimai/kimai/security/advisories/GHSA-jrc6-fmhw-fpq2
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Source reference
Unverified legacy reference
URL: https://www.vulncheck.com/advisories/kimai-before-2.54.0-username-enumeration-via-timing-oracle
Methodology and review provenance
AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.