# CVE-2026-58084: Kernel stack disclosure via timer_settime(2)

> An unprivileged local user can read uninitialized kernel stack memory via timer_settime(2) on FreeBSD, potentially exposing sensitive data.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 19 Aug 2026
- **Updated:** 26 Aug 2026
- **Also known as:** GHSA-p4v3-cw55-5mrc

## What is CVE-2026-58084?

CVE-2026-58084 is a medium-severity vulnerability in Freebsd Freebsd, published on 19 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

To retrieve the previous timer value, the kernel calls realtimer_gettime(), which obtains the current time for the timer's clock.  For a timer using CLOCK_TAI this can fail when no TAI offset has been configured, but the error return was not checked, so the uninitialized output buffer was copied to userspace.

An unprivileged local user can obtain uninitialized kernel stack memory by creating a POSIX timer with CLOCK_TAI and calling timer_settime(2), potentially disclosing sensitive kernel data.

Weakness: CWE-908 (Use of Uninitialized Resource)

## Which versions are affected by CVE-2026-58084?

It affects 1 product.


Products: Freebsd Freebsd.

## How do I fix CVE-2026-58084?

No fix has been published for CVE-2026-58084 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-58084 being exploited?

There is no known exploitation of CVE-2026-58084 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-2026-58084 and fix it if it is affected.

What it is: CVE-2026-58084 is a medium-severity vulnerability in Freebsd Freebsd, published on 19 Aug 2026. 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-2026-58084 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-2026-58084/ (Markdown: https://insights.sbomify.com/CVE-2026-58084/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-58084
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-58084
- OSV: https://osv.dev/vulnerability/CVE-2026-58084

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-58084/
Summaries are generated and may contain mistakes; the official description above is the record.