# CVE-2026-48590: Element and Attribute Names Injected Verbatim into XML Output in xml_builder

> Attackers can inject arbitrary XML markup into generated documents via unescaped element and attribute names in the xml_builder library.

- **Severity:** Low 2.1 (`CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 21 Aug 2026
- **Updated:** 21 Aug 2026
- **Also known as:** EEF-CVE-2026-48590, GHSA-r82p-3q2p-728w

## What is CVE-2026-48590?

CVE-2026-48590 is a low-severity vulnerability in joshnuss xml_builder, published on 21 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

XML Injection vulnerability in joshnuss xml_builder (XmlBuilder module) allows Content Spoofing, XML Injection.

This vulnerability is associated with program files lib/xml_builder.ex and program routines XmlBuilder.generate/1, XmlBuilder.generate/2, XmlBuilder.element/1, XmlBuilder.element/2, XmlBuilder.element/3.

Element names, attribute names, and doctype identifiers are interpolated verbatim into the serialized XML output without validation or escaping of structural characters (<, >, ", ', &). An attacker who can influence a name argument (for example, an element name derived from a JSON object key or an HTTP form field name) can inject arbitrary XML markup including extra elements, comments, and event-handler attributes into the output document.

This issue affects xml_builder: from 0.0.1 before 2.4.1.

Weakness: CWE-91 (XML Injection)

## Which versions are affected by CVE-2026-48590?

1 open source package ship an affected version, including xml_builder.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `xml_builder` | Hex | From 0.0.1 | 2.4.1 |

## How do I fix CVE-2026-48590?

Upgrade xml_builder to 2.4.1 or later.

## Is CVE-2026-48590 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-48590 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-48590 and fix it if it is affected.

What it is: CVE-2026-48590 is a low-severity vulnerability in joshnuss xml_builder, published on 21 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-48590 exists.

Affected packages and fixed versions:
- xml_builder (Hex): affected from 0.0.1; fixed in 2.4.1

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-2026-48590/ (Markdown: https://insights.sbomify.com/CVE-2026-48590/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-48590
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-48590
- OSV: https://osv.dev/vulnerability/CVE-2026-48590

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-48590/
Summaries are generated and may contain mistakes; the official description above is the record.