# CVE-2019-19234: Auth bypass in n/a

> Attackers with sudo access can impersonate users blocked by password hashes, bypassing intended authentication restrictions.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/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:** 19 Dec 2019
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2019-19234, GHSA-vh47-792w-24m4, UBUNTU-CVE-2019-19234

## What is CVE-2019-19234?

CVE-2019-19234 is a high-severity authentication bypass vulnerability in n/a, published on 19 Dec 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In Sudo through 1.8.29, the fact that a user has been blocked (e.g., by using the ! character in the shadow file instead of a password hash) is not considered, allowing an attacker (who has access to a Runas ALL sudoer account) to impersonate any blocked user. NOTE: The software maintainer believes that this CVE is not valid. Disabling local password authentication for a user is not the same as disabling all access to that user--the user may still be able to login via other means (ssh key, kerberos, etc). Both the Linux shadow(5) and passwd(1) manuals are clear on this. Indeed it is a valid use case to have local accounts that are _only_ accessible via sudo and that cannot be logged into with a password. Sudo 1.8.30 added an optional setting to check the _shell_ of the target user (not the encrypted password!) against the contents of /etc/shells but that is not the same thing as preventing access to users with an invalid password hash

## Which versions are affected by CVE-2019-19234?

It affects 1 product.


Products: Sudo Sudo.

## How do I fix CVE-2019-19234?

Apply the vendor's patch.

## Is CVE-2019-19234 being exploited?

There is no known exploitation of CVE-2019-19234 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2019-19232](https://insights.sbomify.com/CVE-2019-19232/): Privilege escalation in n/a (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-19234 and fix it if it is affected.

What it is: CVE-2019-19234 is a high-severity authentication bypass vulnerability in n/a, published on 19 Dec 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-2019-19234 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-2019-19234/ (Markdown: https://insights.sbomify.com/CVE-2019-19234/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-19234
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-19234
- OSV: https://osv.dev/vulnerability/CVE-2019-19234

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-19234/
Summaries are generated and may contain mistakes; the official description above is the record.