# CVE-2018-16868: Information disclosure in gnutls

> A local attacker can exploit a side-channel in GnuTLS to extract plaintext or downgrade TLS connections via a padding oracle attack.

- **Severity:** Medium 4.7 (`CVSS:3.0/AV:P/AC:H/PR:H/UI:N/S:C/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 3 Dec 2018
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2018-16868, GHSA-qjx3-4wr5-3c93, MGASA-2019-0103, SUSE-SU-2019:1351-1, SUSE-SU-2019:1351-2, UBUNTU-CVE-2018-16868, openSUSE-SU-2019:1477-1

## What is CVE-2018-16868?

CVE-2018-16868 is a medium-severity vulnerability in Gnu Gnutls, published on 3 Dec 2018. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A Bleichenbacher type side-channel based padding oracle attack was found in the way gnutls handles verification of RSA decrypted PKCS#1 v1.5 data. An attacker who is able to run process on the same physical core as the victim process, could use this to extract plaintext or in some cases downgrade any TLS connections to a vulnerable server.

Weakness: CWE-203 (Observable Discrepancy)

## Which versions are affected by CVE-2018-16868?

It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `gnutls` | SUSE:Linux Enterprise Module for Basesystem 15 | All versions | 3.6.7-6.11.1 |
| `gnutls` | SUSE:Linux Enterprise Module for Basesystem 15 SP1 | All versions | 3.6.7-6.11.1 |
| `gnutls` | SUSE:Linux Enterprise Module for Desktop Applications 15 | All versions | 3.6.7-6.11.1 |
| `gnutls` | openSUSE:Leap 15.0 | All versions | 3.6.7-lp151.2.3.1 |
| `gnutls` | openSUSE:Leap 15.1 | All versions | 3.6.7-lp151.2.3.1 |

Products: Gnu Gnutls.

## How do I fix CVE-2018-16868?

Apply the vendor's patch.

## Is CVE-2018-16868 being exploited?

There is no known exploitation of CVE-2018-16868 in the wild and no public exploit code.

## Other vulnerabilities in Gnu Gnutls

- [CVE-2008-1948](https://insights.sbomify.com/CVE-2008-1948/): Memory corruption in n/a (critical 10.0)
- [CVE-2017-5334](https://insights.sbomify.com/CVE-2017-5334/): Use after free in n/a (critical 9.8)
- [CVE-2017-5336](https://insights.sbomify.com/CVE-2017-5336/): Memory corruption in n/a (critical 9.8)
- [CVE-2017-5337](https://insights.sbomify.com/CVE-2017-5337/): Memory corruption in n/a (critical 9.8)
- [CVE-2008-1949](https://insights.sbomify.com/CVE-2008-1949/): Null dereference in n/a (critical 9.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-16868 and fix it if it is affected.

What it is: CVE-2018-16868 is a medium-severity vulnerability in Gnu Gnutls, published on 3 Dec 2018. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2018-16868 in the wild and no public exploit code.

Affected product: Gnu Gnutls. 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-2018-16868/ (Markdown: https://insights.sbomify.com/CVE-2018-16868/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-16868
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-16868
- OSV: https://osv.dev/vulnerability/CVE-2018-16868

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-16868/
Summaries are generated and may contain mistakes; the official description above is the record.