# CVE-2020-25577: Memory corruption in FreeBSD

> A buffer overflow in FreeBSD's rtsold allows attackers to cause denial of service or execute code via malformed RDNSS packets.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 29 Mar 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-r8gv-c2f3-665p

## What is CVE-2020-25577?

CVE-2020-25577 is a critical memory corruption vulnerability in Freebsd Freebsd, published on 29 Mar 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In FreeBSD 12.2-STABLE before r368250, 11.4-STABLE before r368253, 12.2-RELEASE before p1, 12.1-RELEASE before p11 and 11.4-RELEASE before p5 rtsold(8) does not verify that the RDNSS option does not extend past the end of the received packet before processing its contents. While the kernel currently ignores such malformed packets, it passes them to userspace programs. Any programs expecting the kernel to do validation may be vulnerable to an overflow.

Weakness: CWE-120 (Buffer Copy without Checking Size of Input)

## Which versions are affected by CVE-2020-25577?

It affects 1 product.


Products: Freebsd Freebsd.

## How do I fix CVE-2020-25577?

No fix has been published for CVE-2020-25577 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-25577 being exploited?

There is no known exploitation of CVE-2020-25577 in the wild and no public exploit code.

## Other vulnerabilities in Freebsd Freebsd

- [CVE-2018-17160](https://insights.sbomify.com/CVE-2018-17160/): Memory corruption in FreeBSD (critical 10.0)
- [CVE-2014-3954](https://insights.sbomify.com/CVE-2014-3954/): Memory corruption in n/a (critical 10.0)
- [CVE-2006-4304](https://insights.sbomify.com/CVE-2006-4304/): Memory corruption in n/a (critical 10.0)
- [CVE-2006-0226](https://insights.sbomify.com/CVE-2006-0226/): Integer overflow in n/a (critical 10.0)
- [CVE-2004-0002](https://insights.sbomify.com/CVE-2004-0002/): Denial of service in n/a (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-25577 and fix it if it is affected.

What it is: CVE-2020-25577 is a critical memory corruption vulnerability in Freebsd Freebsd, published on 29 Mar 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-2020-25577 in the wild and no public exploit code.

Affected product: Freebsd Freebsd. 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-2020-25577/ (Markdown: https://insights.sbomify.com/CVE-2020-25577/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-25577
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-25577
- OSV: https://osv.dev/vulnerability/CVE-2020-25577

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-25577/
Summaries are generated and may contain mistakes; the official description above is the record.