# CVE-2026-101307: Remotely triggerable buffer overflow in tcp_rack

> A remote attacker can trigger a kernel panic in FreeBSD by causing an integer overflow in the TCP RACK stack, leading to a buffer overflow.

- **Severity:** High 8.2 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 15 Oct 2026
- **Updated:** 15 Oct 2026
- **Also known as:** GHSA-gpr4-gr7v-w9p3

## What is CVE-2026-101307?

CVE-2026-101307 is a high-severity vulnerability in Freebsd Freebsd, published on 15 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

When the PCM sample array needs to grow, the RACK stack doubles a 16-bit allocation counter.  Repeated doublings caused the counter to wrap to zero, resulting in a near-zero-length allocation followed by a copy of the existing samples into the undersized buffer.  A remote peer can trigger the expansion by sending a sufficient number of ACKs on an established connection.

A remote attacker who can establish a TCP connection to a system using the RACK stack can trigger an out-of-bounds write of approximately 512 KB in the kernel heap possibly resulting in a kernel panic.

Weakness: CWE-787 (Out-of-bounds Write), CWE-122 (Heap-based Buffer Overflow)

## Which versions are affected by CVE-2026-101307?

It affects 1 product.


Products: Freebsd Freebsd.

## How do I fix CVE-2026-101307?

No fix has been published for CVE-2026-101307 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-101307 being exploited?

There is no known exploitation of CVE-2026-101307 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-2026-101307 and fix it if it is affected.

What it is: CVE-2026-101307 is a high-severity vulnerability in Freebsd Freebsd, published on 15 Oct 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-2026-101307 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-2026-101307/ (Markdown: https://insights.sbomify.com/CVE-2026-101307/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-101307
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-101307
- OSV: https://osv.dev/vulnerability/CVE-2026-101307

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-101307/
Summaries are generated and may contain mistakes; the official description above is the record.