# CVE-2019-8460: Denial of service in OpenBSD

> Attackers can cause a denial of service in OpenBSD by forcing the kernel to process expensive TCP SACK hole chains.

- **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:** No
- **Published:** 26 Aug 2019
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-9q38-5hh6-p5gw

## What is CVE-2019-8460?

CVE-2019-8460 is a high-severity denial of service vulnerability in Openbsd Openbsd, published on 26 Aug 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

OpenBSD kernel version <= 6.5 can be forced to create long chains of TCP SACK holes that causes very expensive calls to tcp_sack_option() for every incoming SACK packet which can lead to a denial of service.

Weakness: CWE-1049 (Excessive Data Query Operations in a Large Data Table)

## Which versions are affected by CVE-2019-8460?

It affects 1 product.


Products: Openbsd Openbsd.

## How do I fix CVE-2019-8460?

No fix has been published for CVE-2019-8460 yet. Limit exposure of the affected software until one is available.

## Is CVE-2019-8460 being exploited?

There is no known exploitation of CVE-2019-8460 in the wild and no public exploit code.

## Other vulnerabilities in Openbsd Openbsd

- [CVE-2007-1365](https://insights.sbomify.com/CVE-2007-1365/): Memory corruption in n/a (critical 10.0)
- [CVE-2004-0220](https://insights.sbomify.com/CVE-2004-0220/): Integer overflow in n/a (critical 10.0)
- [CVE-2004-0083](https://insights.sbomify.com/CVE-2004-0083/): Memory corruption in n/a (critical 10.0)
- [CVE-2004-0084](https://insights.sbomify.com/CVE-2004-0084/): Memory corruption in n/a (critical 10.0)
- [CVE-2001-0284](https://insights.sbomify.com/CVE-2001-0284/): Memory corruption in n/a (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-8460 and fix it if it is affected.

What it is: CVE-2019-8460 is a high-severity denial of service vulnerability in Openbsd Openbsd, published on 26 Aug 2019. 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-2019-8460 in the wild and no public exploit code.

Affected product: Openbsd Openbsd. 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-2019-8460/ (Markdown: https://insights.sbomify.com/CVE-2019-8460/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-8460
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-8460
- OSV: https://osv.dev/vulnerability/CVE-2019-8460

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-8460/
Summaries are generated and may contain mistakes; the official description above is the record.