# CVE-2018-1285: XML External Entity attack in log4net

> Attackers can exploit XML external entity vulnerabilities in Apache log4net configuration parsing to read sensitive data or cause denial of service.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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:** 11 May 2020
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2018-1285, DLA-2211-1, GHSA-2cwj-8chv-9pp9, MGASA-2020-0233, UBUNTU-CVE-2018-1285, USN-4699-1, openSUSE-SU-2024:12311-1

## What is CVE-2018-1285?

CVE-2018-1285 is a critical vulnerability in Fedoraproject Fedora, published on 11 May 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Apache log4net versions before 2.0.10 do not disable XML external entities when parsing log4net configuration files. This allows for XXE-based attacks in applications that accept attacker-controlled log4net configuration files.

Weakness: CWE-611 (Improper Restriction of XML External Entity Reference)

## Which versions are affected by CVE-2018-1285?

2 open source packages ship an affected version, including log4net. It affects 7 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `log4net` | NuGet | All versions | 2.0.10 |
| `log4net` | NuGet | All versions | 2.0.10 |
| `log4net` | openSUSE:Tumbleweed | All versions | 1.2.10-78.1 |

Products: Apache Log4net, Fedoraproject Fedora, Netapp Manageability Software Development Kit, Netapp Snapcenter, Oracle Application Testing Suite, Oracle Hospitality Opera 5, Oracle Hospitality Simphony.

## How do I fix CVE-2018-1285?

Upgrade log4net to 2.0.10 or later.

## Is CVE-2018-1285 being exploited?

There is no known exploitation of CVE-2018-1285 in the wild and no public exploit code.

Public exploit code:

- Test application for CVE-2018-1285 alert for Solarwinds DLLs (github_poc): https://github.com/alex-ermolaev/Log4NetSolarWindsSNMP-

## Other vulnerabilities in Fedoraproject Fedora

- [CVE-2026-40021](https://insights.sbomify.com/CVE-2026-40021/): Apache Log4net: Silent log event loss in XmlLayout and XmlLayoutSchemaLog4J due to unescaped XML 1.0 forbidden characters (medium 6.3)
- [CVE-2026-105239](https://insights.sbomify.com/CVE-2026-105239/): Apache log4net: NUL character truncates EventLogAppender records (medium 5.3)
- [CVE-2026-105240](https://insights.sbomify.com/CVE-2026-105240/): Apache log4net: NUL character truncates OutputDebugStringAppender records (medium 5.3)
- [CVE-2026-105241](https://insights.sbomify.com/CVE-2026-105241/): Apache log4net: Unencodable content discards a whole SmtpPickupDirAppender batch (medium 5.3)
- [CVE-2026-105242](https://insights.sbomify.com/CVE-2026-105242/): Apache log4net: Request validation failure drops the event in the aspnet-request converter (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-1285 and fix it if it is affected.

What it is: CVE-2018-1285 is a critical vulnerability in Fedoraproject Fedora, published on 11 May 2020. 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-2018-1285 in the wild and no public exploit code.

Affected packages and fixed versions:
- log4net (NuGet): affected all versions; fixed in 2.0.10
- log4net (NuGet): affected all versions; fixed in 2.0.10

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-2018-1285/ (Markdown: https://insights.sbomify.com/CVE-2018-1285/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-1285
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-1285
- OSV: https://osv.dev/vulnerability/CVE-2018-1285

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-1285/
Summaries are generated and may contain mistakes; the official description above is the record.