# CVE-2022-23476: Unchecked return value from xmlTextReaderExpand in Nokogiri

> Attackers can cause a denial of service via null pointer exception in Nokogiri when parsing invalid markup with XML::Reader.

- **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:** 8 Dec 2022
- **Updated:** 23 Apr 2025
- **Also known as:** DEBIAN-CVE-2022-23476, GHSA-qv4q-mr5r-qprj

## What is CVE-2022-23476?

CVE-2022-23476 is a high-severity vulnerability in sparklemotion nokogiri, published on 8 Dec 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Nokogiri is an open source XML and HTML library for the Ruby programming language. Nokogiri `1.13.8` and `1.13.9` fail to check the return value from `xmlTextReaderExpand` in the method `Nokogiri::XML::Reader#attribute_hash`. This can lead to a null pointer exception when invalid markup is being parsed. For applications using `XML::Reader` to parse untrusted inputs, this may potentially be a vector for a denial of service attack. Users are advised to upgrade to Nokogiri `>= 1.13.10`. Users may be able to search their code for calls to either `XML::Reader#attributes` or `XML::Reader#attribute_hash` to determine if they are affected.

Weakness: CWE-476 (NULL Pointer Dereference), CWE-252 (Unchecked Return Value)

## Which versions are affected by CVE-2022-23476?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `nokogiri` | RubyGems | From 1.13.8 | 1.13.10 |
| `nokogiri` | RubyGems | From 1.13.8 | 1.13.10 |

Products: Nokogiri Nokogiri.

## How do I fix CVE-2022-23476?

Upgrade nokogiri to 1.13.10 or later.

## Is CVE-2022-23476 being exploited?

There is no known exploitation of CVE-2022-23476 in the wild and no public exploit code.

## Other vulnerabilities in sparklemotion nokogiri

- [CVE-2026-79770](https://insights.sbomify.com/CVE-2026-79770/): Nokogiri before 1.19.3 ReDoS via CSS selector tokenizer (high 8.7)
- [CVE-2021-41098](https://insights.sbomify.com/CVE-2021-41098/): Improper Restriction of XML External Entity Reference (XXE) in Nokogiri on JRuby (high 7.5)
- [CVE-2012-6685](https://insights.sbomify.com/CVE-2012-6685/): Nokogiri is vulnerable to XML External Entity (XXE) attack (high 7.5)
- [CVE-2026-79771](https://insights.sbomify.com/CVE-2026-79771/): Nokogiri before 1.19.3 Memory Leak via XSLT Transform (medium 6.9)
- [CVE-2026-79772](https://insights.sbomify.com/CVE-2026-79772/): Nokogiri before 1.19.1 Unchecked Return Value canonicalize (medium 6.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-23476 and fix it if it is affected.

What it is: CVE-2022-23476 is a high-severity vulnerability in sparklemotion nokogiri, published on 8 Dec 2022. 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-2022-23476 in the wild and no public exploit code.

Affected packages and fixed versions:
- nokogiri (RubyGems): affected from 1.13.8; fixed in 1.13.10
- nokogiri (RubyGems): affected from 1.13.8; fixed in 1.13.10

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-2022-23476/ (Markdown: https://insights.sbomify.com/CVE-2022-23476/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-23476
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-23476
- OSV: https://osv.dev/vulnerability/CVE-2022-23476

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-23476/
Summaries are generated and may contain mistakes; the official description above is the record.