CVE-2026-84364: CWE-400: Uncontrolled Resource Consumption in honojs hono
Description
Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.13.5, when parseBody() expands dot-separated form field names into nested objects with dot-notation parsing enabled, it does not limit the nesting depth or the total number of intermediate objects created. Empty segments are preserved, so one deeply dotted field name can encode one nesting level per byte, while a large number of shallowly dotted fields can create the same amplification across a request. A request body within a normal size limit can therefore allocate an object graph far larger than the request after the body has already been accepted. An unauthenticated attacker who can reach an affected endpoint can send concurrent requests that exhaust the JavaScript heap, terminate the server process, and leave the service unavailable until restart. Dot-notation parsing is not enabled by default, and applications using the default behavior are not affected. This issue is fixed in version 4.13.5.
CVSS v3.1
Score 5.3medium
Affected software
honojs
hono
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Hono is a JavaScript web application framework supporting multiple runtimes. Before version 4.13.5, when the parseBody() function is used with dot-notation parsing enabled, it does not limit the depth of nested objects or the total number of intermediate objects created from dot-separated form field names. Attackers can exploit this by sending requests with deeply or broadly dotted field names, causing the server to allocate an object graph much larger than the request body. This uncontrolled resource consumption can exhaust the JavaScript heap, terminate the server process, and cause a denial of service. The vulnerability requires dot-notation parsing to be enabled, which is not the default setting. The issue is resolved in version 4.13.5.
Potential Impact
An unauthenticated attacker able to send requests to an affected endpoint can cause a denial of service by exhausting server memory and crashing the process. This results in service unavailability until the server is restarted. There is no impact on confidentiality or integrity, only availability is affected.
Mitigation Recommendations
Upgrade to hono version 4.13.5 or later, where this issue is fixed. If upgrading is not immediately possible, disable dot-notation parsing in parseBody(), as the vulnerability only affects configurations with this feature enabled. No other mitigation is specified.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-09-01T16:27:58.128Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6a9737bfacd9273b492c51a7
Added to database: 09/01/2026, 20:38:23 UTC
Last enriched: 09/07/2026, 13:48:40 UTC
Last updated: 10/17/2026, 18:48:23 UTC
Views: 83
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