# CVE-2020-35679: Denial of service in n/a

> Attackers can cause significant memory leaks in OpenSMTPD by sending messages that trigger regex lookups, potentially leading to denial of service.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Dec 2020
- **Updated:** 4 Aug 2024
- **Also known as:** ALPINE-CVE-2020-35679, DEBIAN-CVE-2020-35679, GHSA-42p2-4vv3-9qv4, UBUNTU-CVE-2020-35679

## What is CVE-2020-35679?

CVE-2020-35679 is a high-severity denial of service vulnerability in Fedoraproject Fedora, published on 24 Dec 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

smtpd/table.c in OpenSMTPD before 6.8.0p1 lacks a certain regfree, which might allow attackers to trigger a "very significant" memory leak via messages to an instance that performs many regex lookups.

Weakness: CWE-401 (Missing Release of Memory after Effective Lifetime)

## Which versions are affected by CVE-2020-35679?

It affects 2 products.


Products: Fedoraproject Fedora, Opensmtpd Opensmtpd.

## How do I fix CVE-2020-35679?

Upgrade to a fixed version.

## Is CVE-2020-35679 being exploited?

There is no known exploitation of CVE-2020-35679 in the wild and no public exploit code.

## Other vulnerabilities in Fedoraproject Fedora

- [CVE-2024-4577](https://insights.sbomify.com/CVE-2024-4577/): PHP-CGI OS Command Injection (critical 9.8, exploited in the wild)
- [CVE-2021-39226](https://insights.sbomify.com/CVE-2021-39226/): Grafana Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2019-5544](https://insights.sbomify.com/CVE-2019-5544/): VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2024-4947](https://insights.sbomify.com/CVE-2024-4947/): Google Chromium V8 Type Confusion (critical 9.6, exploited in the wild)
- [CVE-2024-4671](https://insights.sbomify.com/CVE-2024-4671/): Google Chromium Visuals Use-After-Free (critical 9.6, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-35679 and fix it if it is affected.

What it is: CVE-2020-35679 is a high-severity denial of service vulnerability in Fedoraproject Fedora, published on 24 Dec 2020. 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-2020-35679 in the wild and no public exploit code.

Affected product: Fedoraproject Fedora. 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-2020-35679/ (Markdown: https://insights.sbomify.com/CVE-2020-35679/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-35679
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-35679
- OSV: https://osv.dev/vulnerability/CVE-2020-35679

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-35679/
Summaries are generated and may contain mistakes; the official description above is the record.