CVE-2026-29085
Hono: SSE Control Field Injection via CR/LF in writeSSE()
CVSS Score
6.5
EPSS Score
0.0%
EPSS Percentile
0th
Hono is a Web application framework that provides support for any JavaScript runtime. Prior to version 4.12.4, when using streamSSE() in Streaming Helper, the event, id, and retry fields were not validated for carriage return (\r) or newline (\n) characters. Because the SSE protocol uses line breaks as field delimiters, this could allow injection of additional SSE fields within the same event frame if untrusted input was passed into these fields. This issue has been patched in version 4.12.4.
| CWE | CWE-74 |
| Vendor | honojs |
| Product | hono |
| Published | Mar 4, 2026 |
| Last Updated | Mar 5, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None
Affected Versions
honojs / hono
< 4.12.4