h3js h3 up to 1.15.8 injection

Summaryinfo

A vulnerability, which was classified as problematic, has been found in h3js h3 up to 1.15.8. Affected by this vulnerability is an unknown functionality. This manipulation causes injection. This vulnerability is handled as CVE-2026-86252. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability classified as problematic was found in h3js h3 up to 1.15.8. Affected by this vulnerability is an unknown functionality. The manipulation with an unknown input leads to a injection vulnerability. The CWE definition for the vulnerability is CWE-74. The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component. As an impact it is known to affect integrity. The summary by CVE is:

h3 versions before 1.15.9 fail to sanitize carriage return characters in EventStream data and comment fields, allowing attackers to inject arbitrary SSE events by including unsanitized carriage returns. Attackers can inject event type directives, split single push calls into multiple browser-parsed events, or escape comment fields to inject data, bypassing the prior CVE fix that only addressed newline injection.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-86252 since 09/06/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1055 for this issue.

Upgrading to version 1.15.9 or 2.0.1-rc.17 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-72108). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Vendor

• h3js

Name

• h3

Version

• 1.15.0
• 1.15.1
• 1.15.2
• 1.15.3
• 1.15.4
• 1.15.5
• 1.15.6
• 1.15.7
• 1.15.8

Website

• Product: https://github.com/h3js/h3/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Discussion