CVE-2026-49955: Allocation of Resources Without Limits or Throttling in nesquena hermes-webui
Hermes WebUI before version 0.51.270 contains a resource exhaustion vulnerability that allows unauthenticated remote attackers to degrade service availability by repeatedly calling the passkey options endpoint without completing assertion. Attackers can send unlimited POST requests to the authentication endpoint, causing unbounded growth of the challenge store file and excessive CPU and disk I/O through repeated JSON file rewrites.
AI Analysis
Technical Summary
CVE-2026-49955 describes a resource exhaustion vulnerability in nesquena's Hermes WebUI before version 0.51.270. Attackers can send unlimited POST requests to the authentication endpoint's passkey options without completing the assertion process. This leads to unbounded growth of the challenge store file and excessive CPU and disk input/output due to repeated JSON file rewrites, resulting in degraded service availability. The vulnerability requires no authentication and has a CVSS 4.0 base score of 6.9, indicating medium severity.
Potential Impact
Successful exploitation allows unauthenticated attackers to degrade the availability of the Hermes WebUI service by exhausting system resources such as CPU and disk I/O. This can cause denial of service conditions due to the unbounded growth of the challenge store file and repeated JSON file operations.
Mitigation Recommendations
No official patch or remediation level is currently documented. Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, consider implementing rate limiting or other controls on the authentication endpoint to mitigate resource exhaustion risks.
CVE-2026-49955: Allocation of Resources Without Limits or Throttling in nesquena hermes-webui
Description
Hermes WebUI before version 0.51.270 contains a resource exhaustion vulnerability that allows unauthenticated remote attackers to degrade service availability by repeatedly calling the passkey options endpoint without completing assertion. Attackers can send unlimited POST requests to the authentication endpoint, causing unbounded growth of the challenge store file and excessive CPU and disk I/O through repeated JSON file rewrites.
CVSS v4.0
Score 6.9medium
Affected software
pkg:github/nesquena/hermes-webuiRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-49955 describes a resource exhaustion vulnerability in nesquena's Hermes WebUI before version 0.51.270. Attackers can send unlimited POST requests to the authentication endpoint's passkey options without completing the assertion process. This leads to unbounded growth of the challenge store file and excessive CPU and disk input/output due to repeated JSON file rewrites, resulting in degraded service availability. The vulnerability requires no authentication and has a CVSS 4.0 base score of 6.9, indicating medium severity.
Potential Impact
Successful exploitation allows unauthenticated attackers to degrade the availability of the Hermes WebUI service by exhausting system resources such as CPU and disk I/O. This can cause denial of service conditions due to the unbounded growth of the challenge store file and repeated JSON file operations.
Mitigation Recommendations
No official patch or remediation level is currently documented. Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, consider implementing rate limiting or other controls on the authentication endpoint to mitigate resource exhaustion risks.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-06-02T16:30:15.232Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a283e9b8dd33fbd8553f4a9
Added to database: 06/09/2026, 16:26:03 UTC
Last enriched: 07/15/2026, 10:08:27 UTC
Last updated: 07/31/2026, 19:22:59 UTC
Views: 50
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