# CVE-2018-17143: golang.org/x/net/html has Improper Restriction of Operations within the Bounds of a Memory Buffer

> A remote attacker can cause a denial of service via a panic in the Go HTML parser when processing specific malformed template tags.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Sep 2018
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-fcf9-6fv2-fc5v, GO-2022-0193

## What is CVE-2018-17143?

CVE-2018-17143 is a high-severity denial of service vulnerability in Fedoraproject Fedora, published on 17 Sep 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The html package (aka x/net/html) through 2018-09-17 in Go mishandles <template><tBody><isindex/action=0>, leading to a "panic: runtime error" in inBodyIM in parse.go during an html.Parse call.

Weakness: CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2018-17143?

3 open source packages ship an affected version, including golang.org/x/net. It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `golang.org/x/net` | Go | All versions | 0.0.0-20180921000356-2f5d2388922f |
| `golang.org/x/net` | Go | All versions | 0.0.0-20180921000356-2f5d2388922f |
| `golang.org/x/net` | Go | All versions | 0.0.0-20180921000356-2f5d2388922f |

Products: Fedoraproject Fedora, Golang Net.

## How do I fix CVE-2018-17143?

Upgrade golang.org/x/net to 0.0.0-20180921000356-2f5d2388922f or later.

## Is CVE-2018-17143 being exploited?

There is no known exploitation of CVE-2018-17143 in the wild and no public exploit code.

## Other vulnerabilities in Fedoraproject Fedora

- [CVE-2024-4577](https://insights.sbomify.com/CVE-2024-4577/): PHP-CGI OS Command Injection (critical 9.8, exploited in the wild)
- [CVE-2021-39226](https://insights.sbomify.com/CVE-2021-39226/): Grafana Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2019-5544](https://insights.sbomify.com/CVE-2019-5544/): VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2024-4947](https://insights.sbomify.com/CVE-2024-4947/): Google Chromium V8 Type Confusion (critical 9.6, exploited in the wild)
- [CVE-2024-4671](https://insights.sbomify.com/CVE-2024-4671/): Google Chromium Visuals Use-After-Free (critical 9.6, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-17143 and fix it if it is affected.

What it is: CVE-2018-17143 is a high-severity denial of service vulnerability in Fedoraproject Fedora, published on 17 Sep 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2018-17143 in the wild and no public exploit code.

Affected packages and fixed versions:
- golang.org/x/net (Go): affected all versions; fixed in 0.0.0-20180921000356-2f5d2388922f
- golang.org/x/net (Go): affected all versions; fixed in 0.0.0-20180921000356-2f5d2388922f
- golang.org/x/net (Go): affected all versions; fixed in 0.0.0-20180921000356-2f5d2388922f

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2018-17143/ (Markdown: https://insights.sbomify.com/CVE-2018-17143/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-17143
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-17143
- OSV: https://osv.dev/vulnerability/CVE-2018-17143

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-17143/
Summaries are generated and may contain mistakes; the official description above is the record.