# CVE-2026-90583

## Summary

- **CVE ID:** CVE-2026-90583
- **Severity:** MEDIUM
- **CVSS Score:** 5.3 (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)
- **CWE:** CWE-79, CWE-94
- **Published:** Sep 13, 2026
- **Last Modified:** Sep 15, 2026

## Description

A security flaw has been discovered in kagisearch smallweb up to 0ecb9c48edbf98dc7e934b54fbac43869e64b4cf. The affected element is the function index of the file app/sw.py of the component Query String Rendering. Performing a manipulation of the argument qs results in cross site scripting. The attack is possible to be carried out remotely. This product adopts a rolling release strategy to maintain continuous delivery. Therefore, version details for affected or updated releases cannot be specified. The patch is named 00b68144e583f20a6b67e29cf01bc07f57979ffb. It is recommended to apply a patch to fix this issue. Exploitability requires a raw HTTP request carrying unencoded double-quote characters in the query string - Werkzeug's request.query_string returns the raw request-target, and ordinary browsers percent-encode " as %22, so the payload only lands via netcat/curl-style raw sockets.

## Affected Products

- kagisearch — smallweb (0ecb9c48edbf98dc7e934b54fbac43869e64b4cf)

## References

- [CNA](https://vuldb.com/vuln/403168)
- [CNA](https://vuldb.com/vuln/403168/cti)
- [CNA](https://vuldb.com/cve/CVE-2026-90583)
- [CNA](https://vuldb.com/submit/913779)
- [CNA](https://github.com/kagisearch/smallweb/issues/854)
- [CNA](https://github.com/kagisearch/smallweb/commit/00b68144e583f20a6b67e29cf01bc07f57979ffb)
- [CNA](https://github.com/kagisearch/smallweb/)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.28%
- **EPSS Percentile:** 20.7

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._