# CVE-2021-43999: Improper validation of SAML responses

> Attackers can assume other users' identities via improper SAML validation if SAML support is enabled in Apache Guacamole.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 11 Jan 2022
- **Updated:** 4 Aug 2024
- **Also known as:** BIT-guacamole-2021-43999, BIT-guacamole-server-2021-43999, GHSA-v83c-8hcj-4545, UBUNTU-CVE-2021-43999

## What is CVE-2021-43999?

CVE-2021-43999 is a high-severity authentication bypass vulnerability in Apache Guacamole, published on 11 Jan 2022. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Apache Guacamole 1.2.0 and 1.3.0 do not properly validate responses received from a SAML identity provider. If SAML support is enabled, this may allow a malicious user to assume the identity of another Guacamole user.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2021-43999?

2 open source packages ship an affected version, including guacamole and guacamole-server. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `guacamole` | Bitnami | From 1.2.0 to 1.2.0 | None |
| `guacamole-server` | Bitnami | From 1.2.0 to 1.2.0 | None |

Products: Apache Guacamole.

## How do I fix CVE-2021-43999?

No fix has been published for CVE-2021-43999 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-43999 being exploited?

There is no known exploitation of CVE-2021-43999 in the wild and no public exploit code.

## Other vulnerabilities in Apache Guacamole

- [CVE-2017-3158](https://insights.sbomify.com/CVE-2017-3158/): Apache Guacamole Race Condition vulnerability (high 8.1)
- [CVE-2023-43826](https://insights.sbomify.com/CVE-2023-43826/): Apache Guacamole: Integer overflow in handling of VNC image buffers (high 7.5)
- [CVE-2019-19603](https://insights.sbomify.com/CVE-2019-19603/): Null dereference in n/a (high 7.5)
- [CVE-2018-1340](https://insights.sbomify.com/CVE-2018-1340/): Missing Encryption of Sensitive Data in Apache Guacamole (high 7.5)
- [CVE-2024-35164](https://insights.sbomify.com/CVE-2024-35164/): Apache Guacamole: Improper input validation of console codes (medium 6.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-43999 and fix it if it is affected.

What it is: CVE-2021-43999 is a high-severity authentication bypass vulnerability in Apache Guacamole, published on 11 Jan 2022. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-43999 in the wild and no public exploit code.

Affected packages and fixed versions:
- guacamole (Bitnami): affected from 1.2.0 up to 1.2.0; no fix listed
- guacamole-server (Bitnami): affected from 1.2.0 up to 1.2.0; no fix listed

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-2021-43999/ (Markdown: https://insights.sbomify.com/CVE-2021-43999/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-43999
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-43999
- OSV: https://osv.dev/vulnerability/CVE-2021-43999

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-43999/
Summaries are generated and may contain mistakes; the official description above is the record.