# CVE-2016-20011: Security feature bypass in n/a

> Attackers can manipulate RSS feed contents undetected because libgrss fails to verify TLS certificates during downloads.

- **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:** 25 May 2021
- **Updated:** 6 Aug 2024
- **Also known as:** DEBIAN-CVE-2016-20011, GHSA-x2mc-pw6q-5pv7, MGASA-2021-0343, UBUNTU-CVE-2016-20011

## What is CVE-2016-20011?

CVE-2016-20011 is a high-severity vulnerability in n/a, published on 25 May 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

libgrss through 0.7.0 fails to perform TLS certificate verification when downloading feeds, allowing remote attackers to manipulate the contents of feeds without detection. This occurs because of the default behavior of SoupSessionSync.

Weakness: CWE-295 (Improper Certificate Validation)

## Which versions are affected by CVE-2016-20011?

It affects 1 product.


Products: Gnome Libgrss.

## How do I fix CVE-2016-20011?

Upgrade to a fixed version.

## Is CVE-2016-20011 being exploited?

There is no known exploitation of CVE-2016-20011 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2016-20011 and fix it if it is affected.

What it is: CVE-2016-20011 is a high-severity vulnerability in n/a, published on 25 May 2021. 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-2016-20011 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-2016-20011/ (Markdown: https://insights.sbomify.com/CVE-2016-20011/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2016-20011
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2016-20011
- OSV: https://osv.dev/vulnerability/CVE-2016-20011

---
From sbomify Insights: https://insights.sbomify.com/CVE-2016-20011/
Summaries are generated and may contain mistakes; the official description above is the record.