Hydro @hydrooj/ui-default before 4.59.1 contains a stored cross-site scripting vulnerability that allows registered
Source GCVE Database
Not known to be exploited · CVSS 9.3 Critical : upgrade to 4.59.1 as a priority.
Data as of 11 Nov 2026, 22:20 UTC
Thin evidence
One scorer or none| CNA (VulnCheck) | CVSS 4.0 | 9.3 |
|---|---|---|
| CNA (VulnCheck) | CVSS 3.1 | 8.7 |
- Patch
- Available – fixed in 4.59.1
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:N/SC:H/SI:H/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 11 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 11 Nov 2026.
What to do
Upgrade @hydrooj/ui-default to 4.59.1.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| hydro-dev@hydrooj/ui-default | Affected
| Fixed in
|
npm@hydrooj/ui-defaultpkg:npm/@hydrooj/ui-defaultOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available in Hydro @hydrooj/ui-default version 4.59.1 or later. Users should upgrade to version 4.59.1 or above to remediate this vulnerability. No other mitigation guidance is provided.
Description
Hydro @hydrooj/ui-default versions before 4.59.1 have a stored cross-site scripting (XSS) vulnerability. Registered users can inject malicious scripts via double quotes in language-class tokens within markdown-it-xss.ts. This allows attackers to store payloads in their profile bios that execute when viewed by administrators or other users, potentially stealing session cookies and enabling session hijacking.
References
- nvd.nist.gov/vuln/detail/CVE-2026-126800 (opens in a new tab)
- github.com/hydro-dev/Hydro/commit/3bae56fe8edddff12346bcb1c8281269c94688d8 (opens in a new tab)
- github.com/hydro-dev/Hydro/blob/3c8286dd1350fcd00412e95d5b056dbfed64edda/packages/ui-default/backendlib/markdown-it-xss.ts (opens in a new tab)
- vul.yulun.ac.cn/20261107/hydro (opens in a new tab)
- vulncheck.com/advisories/hydro-hydrooj-ui-default-before-4.59.1-stored-xss-via-markdown-language-class (opens in a new tab)