CVE-2026-29085 json
Hono: SSE Control Field Injection via CR/LF in writeSSE()
published 2026-03-04 8 mo ago modified 2026-09-10 1 mo ago also EUVD-2026-9507 , GHSA-p6xx-57qc-3wxr
- cvss
- 6.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 20%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 8 mo ago
Exploit prediction
0.28% chance of exploitation in the next 30 days, higher than 20% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 6.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N |
| GitHub | 3.1 | 6.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | hono | <4.12.4 |
4.12.4 |
Affected products
- honojs hono
Classification
- Weakness
-
- CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component
References
-
github.com
/honojs/hono/commit/f4123ed9ea3c7c52380cc99a079a4d773838846e
web, patch
-
github.com
/honojs/hono/security/advisories/GHSA-p6xx-57qc-3wxr
web, vendor-advisory
-
nvd.nist.gov
/vuln/detail/CVE-2026-29085
advisory
-
github.com
/honojs/hono
package
Sources
- CVE List CVE-2026-29085
- GitHub Advisory GHSA-p6xx-57qc-3wxr
- NVD CVE-2026-29085
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.