# CVE-2017-9050: Out-of-bounds read in nokogiri

> A heap-based buffer over-read in libxml2 allows attackers to cause a denial of service via crafted XML input, affecting applications like PHP.

- **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:** 18 May 2017
- **Updated:** 14 Oct 2026
- **Also known as:** DEBIAN-CVE-2017-9050, ECHO-671f-1ea4-e79b, GHSA-8c56-cpmw-89x7, UBUNTU-CVE-2017-9050

## What is CVE-2017-9050?

CVE-2017-9050 is a high-severity memory corruption vulnerability in Xmlsoft Libxml2, published on 18 May 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

libxml2 20904-GITv2.9.4-16-g0741801 is vulnerable to a heap-based buffer over-read in the xmlDictAddString function in dict.c. This vulnerability causes programs that use libxml2, such as PHP, to crash. This vulnerability exists because of an incomplete fix for CVE-2016-1839.

Weakness: CWE-125 (Out-of-bounds Read), CWE-122 (Heap-based Buffer Overflow)

## Which versions are affected by CVE-2017-9050?

2 open source packages ship an affected version, including nokogiri. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `nokogiri` | RubyGems | All versions | 1.8.1 |
| `nokogiri` | RubyGems | All versions | 1.8.1 |

Products: Xmlsoft Libxml2.

## How do I fix CVE-2017-9050?

Upgrade nokogiri to 1.8.1 or later.

## Is CVE-2017-9050 being exploited?

There is no known exploitation of CVE-2017-9050 in the wild and no public exploit code.

## Other vulnerabilities in Xmlsoft Libxml2

- [CVE-2017-16931](https://insights.sbomify.com/CVE-2017-16931/): XML external entity in n/a (critical 9.8)
- [CVE-2017-8872](https://insights.sbomify.com/CVE-2017-8872/): Information disclosure in n/a (critical 9.1)
- [CVE-2022-49043](https://insights.sbomify.com/CVE-2022-49043/): Use after free in libxml2 (high 8.1)
- [CVE-2026-86140](https://insights.sbomify.com/CVE-2026-86140/): Memory corruption in libxml2 (high 8.0)
- [CVE-2024-34459](https://insights.sbomify.com/CVE-2024-34459/): Memory corruption in n/a (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-9050 and fix it if it is affected.

What it is: CVE-2017-9050 is a high-severity memory corruption vulnerability in Xmlsoft Libxml2, published on 18 May 2017. 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-2017-9050 in the wild and no public exploit code.

Affected packages and fixed versions:
- nokogiri (RubyGems): affected all versions; fixed in 1.8.1
- nokogiri (RubyGems): affected all versions; fixed in 1.8.1

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-2017-9050/ (Markdown: https://insights.sbomify.com/CVE-2017-9050/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-9050
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-9050
- OSV: https://osv.dev/vulnerability/CVE-2017-9050

---
From sbomify Insights: https://insights.sbomify.com/CVE-2017-9050/
Summaries are generated and may contain mistakes; the official description above is the record.