# golang.org/x/net/html Improper Validation of Array Index vulnerability

Advisory record · `GHSA-mv93-wvcp-7m7r`

- **Identifiers:** `GHSA-mv93-wvcp-7m7r` · `CVE-2018-17847` · `CVE-2018-17848` · `GHSA-4r78-hx75-jjj2` · `GO-2022-0197`
- **State:** Confirmed
- **Severity:** CVSS 7.5 High
- **Critical:** No
- **Weakness (CWE):** [CWE-129](https://cwe.mitre.org/data/definitions/129.html)
- **Tags:** [CWE-129](https://agentprime.io/advisories/tag/cwe-129.md)
- **Published:** 13 May 2022
- **Updated:** 10 Sept 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 13 May 2022, 01:26 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `golang.org/x/net` (Go): affected `<0.0.0-20190125002852-4b62a64f59f7`; fixed in `0.0.0-20190125002852-4b62a64f59f7`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> golang.org/x/net (its html package) before 0.0.0-20190125002852-4b62a64f59f7 panics with an index-out-of-range error when parsing certain malformed HTML through html.Parse. An attacker who can supply HTML for the package to parse can crash the program. Upgrade golang.org/x/net to 0.0.0-20190125002852-4b62a64f59f7 or later.

Written 6 Nov 2026.

## 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

- 7.5 High, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`, from GitHub Advisory Database

- **CISA KEV:** Not listed.
- **EPSS:** 0.024, the 83rd percentile, on 10 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:44 UTC: First seen by agentprime
- 31 Oct 2026, 14:44 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-mv93-wvcp-7m7r)

## Sources

- [GitHub Advisory Database: GHSA-mv93-wvcp-7m7r](https://github.com/advisories/GHSA-mv93-wvcp-7m7r)
- [OSV: GHSA-mv93-wvcp-7m7r](https://osv.dev/vulnerability/GHSA-mv93-wvcp-7m7r)
- <https://nvd.nist.gov/vuln/detail/CVE-2018-17848>
- <https://github.com/golang/go/issues/27846>
- <https://go.dev/cl/159397>
- <https://go.dev/issue/27846>
- <https://go.googlesource.com/net/+/4b62a64f59f73840b9ab79204c94fee61cd1ba2c>
- <https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/LREEWY6KNLHRWFZ7OT4HVLMVVCGGUHON>
- <https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UKRCI7WIOCOCD3H7NXWRGIRABTQOZOBK>
- <https://pkg.go.dev/vuln/GO-2022-0197>

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-mv93-wvcp-7m7r>, 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-mv93-wvcp-7m7r/>. Everything for agents: <https://agentprime.io/llms.txt>.