# CVE-2026-118517: HtmlSanitizer allowLinkHosts() / allowMediaHosts() Bypass via URLs Without a Well-Formed Authority: Incomplete Fix for CVE-2026-45066

Advisory record · `PKSA-n87g-t5cn-m1yq`

- **Identifiers:** `PKSA-n87g-t5cn-m1yq` · `CVE-2026-118517`
- **State:** Confirmed
- **Severity:** CVSS 2.3 Low
- **Critical:** No
- **Weakness (CWE):** [CWE-184](https://cwe.mitre.org/data/definitions/184.html) · [CWE-436](https://cwe.mitre.org/data/definitions/436.html)
- **Tags:** [CWE-184](https://agentprime.io/advisories/tag/cwe-184.md) · [CWE-436](https://agentprime.io/advisories/tag/cwe-436.md)
- **Published:** 4 Nov 2026
- **Updated:** 4 Nov 2026
- **Reviewed by a person:** No

Published by Packagist at 4 Nov 2026, 11:23 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `symfony/html-sanitizer` (Packagist): affected `>=6.1.0, <6.2.0 || >=6.2.0, <6.3.0 || >=6.3.0, <6.4.0 || >=6.4.0, <6.4.50 || >=7.0.0, <7.1.0 || >=7.1.0, <7.2.0 || >=7.2.0, <7.3.0 || >=7.3.0, <7.4.0 || >=7.4.0, <7.4.23 || >=8.0.0, <8.1.0 || >=8.1.0, <8.1.11`; fixed in `6.2.0`, `6.3.0`, `6.4.0`, `6.4.50`, `7.1.0`, `7.2.0`, `7.3.0`, `7.4.0`, `7.4.23`, `8.1.0`, `8.1.11`

## 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

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

- **CISA KEV:** Not listed.
- **EPSS:** No score.

## Timeline

- 4 Nov 2026, 11:23 UTC: [Confirmed by Packagist](https://symfony.com/cve-2026-118517)
- 4 Nov 2026, 19:23 UTC: First seen by agentprime
- 5 Nov 2026, 16:26 UTC: [Confirmed by the CVE List](https://www.cve.org/CVERecord?id=CVE-2026-118517)
- 5 Nov 2026, 17:17 UTC: [Confirmed by NVD](https://nvd.nist.gov/vuln/detail/CVE-2026-118517)

## Sources

- [OSV: PKSA-n87g-t5cn-m1yq](https://osv.dev/vulnerability/PKSA-n87g-t5cn-m1yq)
- <https://symfony.com/cve-2026-118517>

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/PKSA-n87g-t5cn-m1yq>, 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/PKSA-n87g-t5cn-m1yq/>. Everything for agents: <https://agentprime.io/llms.txt>.