# CVE-2026-23747: Golioth Firmware SDK < 0.22.0 Payload Utils Stack-based Buffer Overflow

> A stack-based buffer overflow in Golioth Firmware SDK allows remote attackers to cause a denial of service via malicious payloads.

- **Severity:** Medium 6.3 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/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:** 26 Feb 2026
- **Updated:** 14 Jul 2026
- **Also known as:** GHSA-5wx9-6p5v-7r76

## What is CVE-2026-23747?

CVE-2026-23747 is a medium-severity memory corruption vulnerability in Golioth Firmware SDK, published on 26 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Golioth Firmware SDK version 0.10.0 prior to 0.22.0, fixed in commit 48f521b, contain a stack-based buffer overflow in Payload Utils. The golioth_payload_as_int() and golioth_payload_as_float() helpers copy network-supplied payload data into fixed-size stack buffers using memcpy() with a length derived from payload_size. The only length checks are guarded by assert(); in release builds, the asserts are compiled out and memcpy() may copy an unbounded payload_size. Payloads larger than 12 bytes (int) or 32 bytes (float) can overflow the stack, resulting in a crash/denial of service. This is reachable via LightDB State on_payload with a malicious server or MITM.

Weakness: CWE-121 (Stack-based Buffer Overflow)

## Which versions are affected by CVE-2026-23747?


## How do I fix CVE-2026-23747?

No fix has been published for CVE-2026-23747 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-23747 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-23747 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-23747 and fix it if it is affected.

What it is: CVE-2026-23747 is a medium-severity memory corruption vulnerability in Golioth Firmware SDK, published on 26 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-23747 exists.

Affected product: Golioth Firmware SDK. 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-2026-23747/ (Markdown: https://insights.sbomify.com/CVE-2026-23747/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-23747
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-23747
- OSV: https://osv.dev/vulnerability/CVE-2026-23747

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-23747/
Summaries are generated and may contain mistakes; the official description above is the record.