1. Home
  2. Vulnerabilities
  3. CVE-2026-29085
6.5
MEDIUM CVSS 3.1
CVE-2026-29085
Hono: SSE Control Field Injection via CR/LF in writeSSE()
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.

INFO

Published Date :

March 4, 2026, 11:16 p.m.

Last Modified :

March 6, 2026, 6:03 p.m.

Remotely Exploit :

Yes !

Source :

[email protected]
Affected Products

The following products are affected by CVE-2026-29085 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Hono hono
: Total Affected Vendor : 1 | Products : 1
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 MEDIUM [email protected]
Solution
Update Hono to version 4.12.4 to fix SSE stream injection vulnerability.
  • Update Hono to version 4.12.4 or later.
  • Validate input for SSE event, id, and retry fields.
  • Sanitize input for carriage return and newline characters.
Public PoC/Exploit Available at Github

CVE-2026-29085 has a 1 public PoC/Exploit available at Github. Go to the Public Exploits tab to see the list.

References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-29085.

URL Resource
https://github.com/honojs/hono/commit/f4123ed9ea3c7c52380cc99a079a4d773838846e Patch
https://github.com/honojs/hono/security/advisories/GHSA-p6xx-57qc-3wxr Vendor Advisory
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-29085 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-29085 weaknesses.

CAPEC-3: Using Leading 'Ghost' Character Sequences to Bypass Input Filters Using Leading 'Ghost' Character Sequences to Bypass Input Filters CAPEC-6: Argument Injection Argument Injection CAPEC-7: Blind SQL Injection Blind SQL Injection CAPEC-8: Buffer Overflow in an API Call Buffer Overflow in an API Call CAPEC-9: Buffer Overflow in Local Command-Line Utilities Buffer Overflow in Local Command-Line Utilities CAPEC-10: Buffer Overflow via Environment Variables Buffer Overflow via Environment Variables CAPEC-13: Subverting Environment Variable Values Subverting Environment Variable Values CAPEC-14: Client-side Injection-induced Buffer Overflow Client-side Injection-induced Buffer Overflow CAPEC-24: Filter Failure through Buffer Overflow Filter Failure through Buffer Overflow CAPEC-28: Fuzzing Fuzzing CAPEC-34: HTTP Response Splitting HTTP Response Splitting CAPEC-42: MIME Conversion MIME Conversion CAPEC-43: Exploiting Multiple Input Interpretation Layers Exploiting Multiple Input Interpretation Layers CAPEC-45: Buffer Overflow via Symbolic Links Buffer Overflow via Symbolic Links CAPEC-46: Overflow Variables and Tags Overflow Variables and Tags CAPEC-47: Buffer Overflow via Parameter Expansion Buffer Overflow via Parameter Expansion CAPEC-51: Poison Web Service Registry Poison Web Service Registry CAPEC-52: Embedding NULL Bytes Embedding NULL Bytes CAPEC-53: Postfix, Null Terminate, and Backslash Postfix, Null Terminate, and Backslash CAPEC-64: Using Slashes and URL Encoding Combined to Bypass Validation Logic Using Slashes and URL Encoding Combined to Bypass Validation Logic CAPEC-67: String Format Overflow in syslog() String Format Overflow in syslog() CAPEC-71: Using Unicode Encoding to Bypass Validation Logic Using Unicode Encoding to Bypass Validation Logic CAPEC-72: URL Encoding URL Encoding CAPEC-76: Manipulating Web Input to File System Calls Manipulating Web Input to File System Calls CAPEC-78: Using Escaped Slashes in Alternate Encoding Using Escaped Slashes in Alternate Encoding CAPEC-79: Using Slashes in Alternate Encoding Using Slashes in Alternate Encoding CAPEC-80: Using UTF-8 Encoding to Bypass Validation Logic Using UTF-8 Encoding to Bypass Validation Logic CAPEC-83: XPath Injection XPath Injection CAPEC-84: XQuery Injection XQuery Injection CAPEC-101: Server Side Include (SSI) Injection Server Side Include (SSI) Injection CAPEC-105: HTTP Request Splitting HTTP Request Splitting CAPEC-108: Command Line Execution through SQL Injection Command Line Execution through SQL Injection CAPEC-120: Double Encoding Double Encoding CAPEC-135: Format String Injection Format String Injection CAPEC-250: XML Injection XML Injection CAPEC-267: Leverage Alternate Encoding Leverage Alternate Encoding CAPEC-273: HTTP Response Smuggling HTTP Response Smuggling

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Profile Photo
tao-lian/openclaw

None

Dockerfile

Updated: 7 hours, 37 minutes ago
1 stars 0 fork 0 watcher
Born at : Feb. 10, 2026, 8:23 p.m. This repo has been linked 10 different CVEs too.

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-29085 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-29085 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • Initial Analysis by [email protected]

    Mar. 06, 2026

    Action Type Old Value New Value
    Added CPE Configuration OR *cpe:2.3:a:hono:hono:*:*:*:*:*:node.js:*:* versions up to (excluding) 4.12.4
    Added Reference Type GitHub, Inc.: https://github.com/honojs/hono/commit/f4123ed9ea3c7c52380cc99a079a4d773838846e Types: Patch
    Added Reference Type GitHub, Inc.: https://github.com/honojs/hono/security/advisories/GHSA-p6xx-57qc-3wxr Types: Vendor Advisory
  • New CVE Received by [email protected]

    Mar. 04, 2026

    Action Type Old Value New Value
    Added 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.
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
    Added CWE CWE-74
    Added Reference https://github.com/honojs/hono/commit/f4123ed9ea3c7c52380cc99a079a4d773838846e
    Added Reference https://github.com/honojs/hono/security/advisories/GHSA-p6xx-57qc-3wxr
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
Base CVSS Score: 6.5
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact