Vulnerability DatabaseCVE-2026-126800
Mend.io Vulnerability Database
The largest open source vulnerability database
What is a Vulnerability ID?
New vulnerability? Tell us about it!
CVE-2026-126800
Published:November 11, 2026
Updated:November 14, 2026
Hydro @hydrooj/ui-default before 4.59.1 contains a stored cross-site scripting vulnerability that allows registered users to inject script by placing double quotes in language- class tokens within markdown-it-xss.ts. Attackers can store a payload in their profile bio that executes when administrators or other users view it, stealing the non-httpOnly sid session cookie for session hijacking.
Affected Packages
@hydrooj/ui-default (NPM):
Affected version(s) >=4.54.4 <4.59.1
Fix Suggestion:
Update to version 4.59.1
Related Resources (6)
https://nvd.nist.gov/vuln/detail/CVE-2026-126800
https://www.vulncheck.com/advisories/hydro-hydrooj-ui-default-before-4.59.1-stored-xss-via-markdown-language-class
https://github.com/hydro-dev/Hydro/commit/3bae56fe8edddff12346bcb1c8281269c94688d8
https://vul.yulun.ac.cn/20261107/hydro/
https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/126xxx/CVE-2026-126800.json
https://github.com/hydro-dev/Hydro/blob/3c8286dd1350fcd00412e95d5b056dbfed64edda/packages/ui-default/backendlib/markdown-it-xss.ts#L150-L157
Do you need more information?
Contact Us
CVSS v4
Base Score:
9.3
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
LOW
User Interaction
PASSIVE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
HIGH
Vulnerable System Availability
NONE
Subsequent System Confidentiality
HIGH
Subsequent System Integrity
HIGH
Subsequent System Availability
NONE
CVSS v3
Base Score:
8.7
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
NONE
Weakness Type (CWE)
Improper Neutralization of Input During Web Page Generation
CWE-79
EPSS
Base Score:
0.31