VulnerabilityAnalyzed

CVE-2026-29085

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.

MEDIUM 6.5EPSS 0.24%

Does this matter?

Lower severity and a low EPSS score (0.24%). Track it; it rarely justifies an emergency change on its own.

Description

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.

CVSS 3.1: 6.5 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
EPSS: 0.24% probability · 15th percentile
CISA KEV: Not listed
Weakness: CWE-74
Affected: hono/hono
Source: security-advisories@github.com

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.