# Crass: Incorrect tokenization of bad URLs enables CSS sanitizer bypass

Advisory record · `GHSA-pq4g-8rxf-4g29`

- **Identifiers:** `GHSA-pq4g-8rxf-4g29` · `CVE-2026-116695`
- **State:** Confirmed
- **Severity:** CVSS 5.3 Medium
- **Critical:** No
- **Weakness (CWE):** [CWE-436](https://cwe.mitre.org/data/definitions/436.html)
- **Tags:** [CWE-436](https://agentprime.io/advisories/tag/cwe-436.md)
- **Published:** 28 Oct 2026
- **Updated:** 28 Oct 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 28 Oct 2026, 22:42 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `crass` (RubyGems): affected `<1.0.8`; fixed in `1.0.8`

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 5.3 Medium, CVSS 4.0: `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0035, the 29th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 27 Oct 2026, 20:10 UTC: [Confirmed by the CVE List](https://www.cve.org/CVERecord?id=CVE-2026-116695)
- 27 Oct 2026, 21:18 UTC: [Confirmed by NVD](https://nvd.nist.gov/vuln/detail/CVE-2026-116695)
- 31 Oct 2026, 14:21 UTC: First seen by agentprime
- 31 Oct 2026, 14:21 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-pq4g-8rxf-4g29)

## Sources

- [GitHub Advisory Database: GHSA-pq4g-8rxf-4g29](https://github.com/advisories/GHSA-pq4g-8rxf-4g29)
- [OSV: GHSA-pq4g-8rxf-4g29](https://osv.dev/vulnerability/GHSA-pq4g-8rxf-4g29)
- <https://github.com/rgrove/crass/security/advisories/GHSA-pq4g-8rxf-4g29>
- <https://nvd.nist.gov/vuln/detail/CVE-2026-116695>
- <https://github.com/rgrove/crass/commit/689fc45c632fdf3803b2f4e844ffc9cca3b08f34>
- <https://github.com/rgrove/crass>
- <https://github.com/rgrove/crass/releases/tag/v1.0.8>
- <https://github.com/rubysec/ruby-advisory-db/blob/master/gems/crass/GHSA-pq4g-8rxf-4g29.yml>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-pq4g-8rxf-4g29>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-pq4g-8rxf-4g29/>. Everything for agents: <https://agentprime.io/llms.txt>.