# CVE-2023-28848: CSRF protection on user_oidc login returned the expected token in case of an error

> An attacker can bypass CSRF protection in the Nextcloud user_oidc plugin by reusing state tokens, potentially allowing unauthorized actions.

- **Severity:** Medium 4.8 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 4 Apr 2023
- **Updated:** 11 Feb 2025
- **Also known as:** GHSA-52hv-xw32-wf7f

## What is CVE-2023-28848?

CVE-2023-28848 is a medium-severity vulnerability in nextcloud security-advisories, published on 4 Apr 2023. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.

### Official description

user_oidc is the OIDC connect user backend for Nextcloud, an open source collaboration platform. A vulnerability in versions 1.0.0 until 1.3.0 effectively allowed an attacker to bypass the state protection as they could just copy the expected state token from the first request to their second request. Users should upgrade user_oidc to 1.3.0 to receive a patch for the issue. No known workarounds are available.

Weakness: CWE-352 (Cross-Site Request Forgery)

## Which versions are affected by CVE-2023-28848?

It affects 1 product.


Products: Nextcloud User Oidc.

## How do I fix CVE-2023-28848?

No fix has been published for CVE-2023-28848 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-28848 being exploited?

There is no known exploitation of CVE-2023-28848 in the wild and no public exploit code.

## Other vulnerabilities in nextcloud security-advisories

- [CVE-2023-32074](https://insights.sbomify.com/CVE-2023-32074/): Nextcloud user_oidc app is missing brute force protection (high 8.0)
- [CVE-2024-37312](https://insights.sbomify.com/CVE-2024-37312/): Nextcloud user_oidc app's ID4me feature is available even when disabled (medium 6.3)
- [CVE-2024-37886](https://insights.sbomify.com/CVE-2024-37886/): Nextcloud user_oidc's ID4me does not validate signature or expiration (medium 5.4)
- [CVE-2023-39953](https://insights.sbomify.com/CVE-2023-39953/): Issuer not verified from obtained token in user_oidc (medium 4.8)
- [CVE-2026-45284](https://insights.sbomify.com/CVE-2026-45284/): Nextcloud: Wrong condition in the User OIDC app's LdapService allowed deleted LDAP users to authenticate (medium 4.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-28848 and fix it if it is affected.

What it is: CVE-2023-28848 is a medium-severity vulnerability in nextcloud security-advisories, published on 4 Apr 2023. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2023-28848 in the wild and no public exploit code.

Affected product: nextcloud security-advisories. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2023-28848/ (Markdown: https://insights.sbomify.com/CVE-2023-28848/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-28848
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-28848
- OSV: https://osv.dev/vulnerability/CVE-2023-28848

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-28848/
Summaries are generated and may contain mistakes; the official description above is the record.