# CVE-2026-58086: ktrace(2) privilege incorrectly validated in jails

> An unprivileged user in a FreeBSD jail can modify or disable ktrace flags of a jailed root user, bypassing intended privilege restrictions.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 19 Aug 2026
- **Updated:** 27 Aug 2026
- **Also known as:** GHSA-5q67-rff6-c784

## What is CVE-2026-58086?

CVE-2026-58086 is a high-severity vulnerability in Freebsd Freebsd, published on 19 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

As an inadvertent side effect of an unrelated code change, PRIV_KTRACE was always denied to a jailed root user.  Tracing configured by a jailed root user was therefore not flagged as privileged.

An unprivileged user in a jail that has permission to debug the target process can modify the jailed root user's ktrace(2) flags, or disable tracing outright.  A jailed root user therefore cannot reliably trace unprivileged processes.

Weakness: CWE-273 (Improper Check for Dropped Privileges)

## Which versions are affected by CVE-2026-58086?

It affects 1 product.


Products: Freebsd Freebsd.

## How do I fix CVE-2026-58086?

No fix has been published for CVE-2026-58086 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-58086 being exploited?

There is no known exploitation of CVE-2026-58086 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-2026-58086 and fix it if it is affected.

What it is: CVE-2026-58086 is a high-severity vulnerability in Freebsd Freebsd, published on 19 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-58086 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-2026-58086/ (Markdown: https://insights.sbomify.com/CVE-2026-58086/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-58086
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-58086
- OSV: https://osv.dev/vulnerability/CVE-2026-58086

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-58086/
Summaries are generated and may contain mistakes; the official description above is the record.