# CVE-2017-17536: Command injection in n/a

> Remote attackers can execute arbitrary code in Phabricator by exploiting unblocked Mercurial flags in branch names.

- **Severity:** High 8.8 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:R/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:** A user has to click or open something
- **Fix available:** No
- **Published:** 11 Dec 2017
- **Updated:** 16 Sep 2024
- **Also known as:** DEBIAN-CVE-2017-17536, GHSA-j2x8-qgjm-w8gp, UBUNTU-CVE-2017-17536

## What is CVE-2017-17536?

CVE-2017-17536 is a high-severity command injection vulnerability in n/a, published on 11 Dec 2017. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Phabricator before 2017-11-10 does not block the --config and --debugger flags to the Mercurial hg program, which allows remote attackers to execute arbitrary code by using the web UI to browse a branch whose name begins with a --config= or --debugger= substring.

## Which versions are affected by CVE-2017-17536?

It affects 1 product.


Products: Phacility Phabricator.

## How do I fix CVE-2017-17536?

No fix has been published for CVE-2017-17536 yet. Limit exposure of the affected software until one is available.

## Is CVE-2017-17536 being exploited?

There is no known exploitation of CVE-2017-17536 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-17536 and fix it if it is affected.

What it is: CVE-2017-17536 is a high-severity command injection vulnerability in n/a, published on 11 Dec 2017. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2017-17536 in the wild and no public exploit code.

Affected product: n/a. 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-2017-17536/ (Markdown: https://insights.sbomify.com/CVE-2017-17536/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-17536
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-17536
- OSV: https://osv.dev/vulnerability/CVE-2017-17536

---
From sbomify Insights: https://insights.sbomify.com/CVE-2017-17536/
Summaries are generated and may contain mistakes; the official description above is the record.