# CVE-2017-12635: Privilege escalation in Apache CouchDB

> Non-admin users can escalate to admin privileges by exploiting JSON parser differences in Apache CouchDB, potentially leading to full system compromise.

- **Severity:** Critical 9.8 (`CVSS:3.0/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:** 14 Nov 2017
- **Updated:** 17 Sep 2024
- **Also known as:** GHSA-f3p2-qqmm-jg8f, UBUNTU-CVE-2017-12635

## What is CVE-2017-12635?

CVE-2017-12635 is a critical vulnerability in Apache CouchDB, published on 14 Nov 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Due to differences in the Erlang-based JSON parser and JavaScript-based JSON parser, it is possible in Apache CouchDB before 1.7.0 and 2.x before 2.1.1 to submit _users documents with duplicate keys for 'roles' used for access control within the database, including the special case '_admin' role, that denotes administrative users. In combination with CVE-2017-12636 (Remote Code Execution), this can be used to give non-admin users access to arbitrary shell commands on the server as the database system user. The JSON parser differences result in behaviour that if two 'roles' keys are available in the JSON, the second one will be used for authorising the document write, but the first 'roles' key is used for subsequent authorization for the newly created user. By design, users can not assign themselves roles. The vulnerability allows non-admin users to give themselves admin privileges.

Weakness: CWE-269 (Improper Privilege Management)

## Which versions are affected by CVE-2017-12635?

It affects 1 product.


Products: Apache Couchdb.

## How do I fix CVE-2017-12635?

Upgrade to a fixed version.

## Is CVE-2017-12635 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2017-12635 exists.

Public exploit code:

- Case study and POC of CVE-2017-12635: Apache CouchDB 1.7.0 / 2.x < 2.1.1 - Remote Privilege Escalation (github_poc): https://github.com/assalielmehdi/CVE-2017-12635
- https://github.com/cyberharsh/Apache-couchdb-CVE-2017-12635 (github_poc): https://github.com/cyberharsh/Apache-couchdb-CVE-2017-12635
- Apache CouchDB Arbitrary Command Execution (metasploit)
- Apache CouchDB 1.7.0 / 2.x < 2.1.1 - Remote Privilege Escalation (exploitdb)
- Apache CouchDB - Arbitrary Command Execution (Metasploit) (exploitdb)
- Apache CouchDB - Arbitrary Command Execution (Metasploit) (exploitdb)

## Other vulnerabilities in Apache CouchDB

- [CVE-2022-24706](https://insights.sbomify.com/CVE-2022-24706/): Apache CouchDB Insecure Default Initialization of Resource (critical 9.8, exploited in the wild)
- [CVE-2020-1955](https://insights.sbomify.com/CVE-2020-1955/): Auth bypass in Apache CouchDB (critical 9.8)
- [CVE-2018-14889](https://insights.sbomify.com/CVE-2018-14889/): Code injection in n/a (high 7.8)
- [CVE-2016-8742](https://insights.sbomify.com/CVE-2016-8742/): Privilege escalation in Apache CouchDB (high 7.8)
- [CVE-2021-38295](https://insights.sbomify.com/CVE-2021-38295/): Privilege escalation vulnerability when using HTML attachments (high 7.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-12635 and fix it if it is affected.

What it is: CVE-2017-12635 is a critical vulnerability in Apache CouchDB, published on 14 Nov 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2017-12635 exists.

Affected product: Apache CouchDB. 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-2017-12635/ (Markdown: https://insights.sbomify.com/CVE-2017-12635/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-12635
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-12635
- OSV: https://osv.dev/vulnerability/CVE-2017-12635

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From sbomify Insights: https://insights.sbomify.com/CVE-2017-12635/
Summaries are generated and may contain mistakes; the official description above is the record.