# CVE-2023-28853: Mastodon's blind LDAP injection in login allows the attacker to leak arbitrary attributes from LDAP database

> Attackers can leak arbitrary LDAP attributes via blind injection during login if LDAP authentication is enabled.

- **Severity:** High 7.7 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 4 Apr 2023
- **Updated:** 13 Feb 2025
- **Also known as:** BIT-mastodon-2023-28853, GHSA-38g9-pfm9-gfqv

## What is CVE-2023-28853?

CVE-2023-28853 is a high-severity vulnerability in mastodon, published on 4 Apr 2023. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Mastodon is a free, open-source social network server based on ActivityPub Mastodon allows configuration of LDAP for authentication. Starting in version 2.5.0 and prior to versions 3.5.8, 4.0.4, and 4.1.2, the LDAP query made during login is insecure and the attacker can perform LDAP injection attack to leak arbitrary attributes from LDAP database. This issue is fixed in versions 3.5.8, 4.0.4, and 4.1.2.

Weakness: CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component), CWE-90 (Improper Neutralization of Special Elements used in an LDAP Query)

## Which versions are affected by CVE-2023-28853?

1 open source package ship an affected version, including mastodon. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `mastodon` | Bitnami | From 2.5.0 | 3.5.8, 4.0.4, 4.1.2 |

Products: Joinmastodon Mastodon.

## How do I fix CVE-2023-28853?

Upgrade mastodon to a fixed version for your release line: 3.5.8, 4.0.4 or 4.1.2.

## Is CVE-2023-28853 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-28853 exists.

## Other vulnerabilities in mastodon

- [CVE-2023-36460](https://insights.sbomify.com/CVE-2023-36460/): Mastodon vulnerable to arbitrary file creation through media attachments (critical 10.0)
- [CVE-2022-2166](https://insights.sbomify.com/CVE-2022-2166/): Improper Restriction of Excessive Authentication Attempts in mastodon/mastodon (critical 9.8)
- [CVE-2022-24307](https://insights.sbomify.com/CVE-2022-24307/): Missing authorization in n/a (critical 9.8)
- [CVE-2018-21018](https://insights.sbomify.com/CVE-2018-21018/): Auth bypass in n/a (critical 9.8)
- [CVE-2024-23832](https://insights.sbomify.com/CVE-2024-23832/): Mastodon Remote user impersonation and takeover (critical 9.4)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-28853 and fix it if it is affected.

What it is: CVE-2023-28853 is a high-severity vulnerability in mastodon, published on 4 Apr 2023. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-28853 exists.

Affected packages and fixed versions:
- mastodon (Bitnami): affected from 2.5.0; fixed in 3.5.8, 4.0.4, 4.1.2

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-2023-28853/ (Markdown: https://insights.sbomify.com/CVE-2023-28853/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-28853
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-28853
- OSV: https://osv.dev/vulnerability/CVE-2023-28853

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-28853/
Summaries are generated and may contain mistakes; the official description above is the record.