# CVE-2018-20745: Yii Incorrectly Implements CORS

> Yii framework incorrectly handles wildcard CORS policies by reflecting arbitrary origins, potentially allowing unauthorized cross-origin requests.

- **Severity:** Medium 5.9 (`CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 28 Jan 2019
- **Updated:** 17 Sep 2024
- **Also known as:** GHSA-cr6r-6xm9-ww22

## What is CVE-2018-20745?

CVE-2018-20745 is a medium-severity vulnerability in n/a, published on 28 Jan 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Yii 2.x through 2.0.15.1 actively converts a wildcard CORS policy into reflecting an arbitrary Origin header value, which is incompatible with the CORS security design, and could lead to CORS misconfiguration security problems.

Weakness: CWE-346 (Origin Validation Error)

## Which versions are affected by CVE-2018-20745?

2 open source packages ship an affected version, including yiisoft/yii2. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `yiisoft/yii2` | Packagist | All versions | 2.0.16 |
| `yiisoft/yii2` | Packagist | All versions | 2.0.16 |

Products: Yiiframework Yii.

## How do I fix CVE-2018-20745?

Upgrade yiisoft/yii2 to 2.0.16 or later.

## Is CVE-2018-20745 being exploited?

There is no known exploitation of CVE-2018-20745 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2024-58136](https://insights.sbomify.com/CVE-2024-58136/): Yiiframework Yii Improper Protection of Alternate Path (critical 9.0, exploited in the wild)
- [CVE-2015-5467](https://insights.sbomify.com/CVE-2015-5467/): Yii2 allows attackers to execute any local .php file via a relative path in the view parameter (critical 9.8)
- [CVE-2023-26750](https://insights.sbomify.com/CVE-2023-26750/): SQL injection in n/a (critical 9.8)
- [CVE-2018-7269](https://insights.sbomify.com/CVE-2018-7269/): Yii SQL injection vulnerability (critical 9.8)
- [CVE-2018-8073](https://insights.sbomify.com/CVE-2018-8073/): yii2-redis Potential Remote code execution (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-20745 and fix it if it is affected.

What it is: CVE-2018-20745 is a medium-severity vulnerability in n/a, published on 28 Jan 2019. 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-2018-20745 in the wild and no public exploit code.

Affected packages and fixed versions:
- yiisoft/yii2 (Packagist): affected all versions; fixed in 2.0.16
- yiisoft/yii2 (Packagist): affected all versions; fixed in 2.0.16

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-2018-20745/ (Markdown: https://insights.sbomify.com/CVE-2018-20745/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-20745
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-20745
- OSV: https://osv.dev/vulnerability/CVE-2018-20745

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-20745/
Summaries are generated and may contain mistakes; the official description above is the record.