# CVE-2026-58081: Heap based buffer overflow in iconv(3)

> Heap buffer overflow in FreeBSD iconv allows attackers to execute code or crash applications processing untrusted input via specific encodings.

- **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:** 19 Aug 2026
- **Updated:** 26 Aug 2026

## What is CVE-2026-58081?

CVE-2026-58081 is a critical memory corruption vulnerability in Freebsd Freebsd, published on 19 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Several encoding modules, including HZ, UTF-7, VIQR, and ZW, did not properly check the size of the caller-supplied output buffer before writing converted characters.

An application that uses iconv(3) to convert untrusted input to or from one of the affected encodings may be vulnerable to buffer overflows if it uses one of the affected encoding modules.

Weakness: CWE-122 (Heap-based Buffer Overflow)

## Which versions are affected by CVE-2026-58081?

It affects 1 product.


Products: Freebsd Freebsd.

## How do I fix CVE-2026-58081?

No fix has been published for CVE-2026-58081 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-58081 being exploited?

There is no known exploitation of CVE-2026-58081 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-2026-58081 and fix it if it is affected.

What it is: CVE-2026-58081 is a critical memory corruption vulnerability in Freebsd Freebsd, published on 19 Aug 2026. 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-2026-58081 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-2026-58081/ (Markdown: https://insights.sbomify.com/CVE-2026-58081/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-58081
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-58081
- OSV: https://osv.dev/vulnerability/CVE-2026-58081

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-58081/
Summaries are generated and may contain mistakes; the official description above is the record.