# CVE-2026-23748: Golioth Firmware SDK out-of-bounds read in LightDB State string parsing

Source: https://junglewise.ai/threats/cve-2026-23748-golioth-firmware-sdk-out-of-bounds-read-in-lightdb-state-string  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-02-26. Updated: 2026-07-14  
License: CC BY 4.0 with a link back

CVE-2026-23748 · Severity: low · CVSS 3.7 · Published 2026-02-26

Golioth Firmware SDK, a software kit used to build and connect IoT devices to the Golioth cloud platform, contains a flaw in how it handles data from the LightDB State service. A malicious server or an attacker intercepting network traffic can send a specially crafted message that causes the device to crash. This results in a denial-of-service condition, potentially disrupting the operations of connected hardware.

Technologies: [Golioth Firmware SDK](https://junglewise.ai/threats/technologies/firmware-sdk). Vendors: [Golioth](https://junglewise.ai/threats/vendors/golioth).

## Quick answers

**Is CVE-2026-23748 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-23748 being exploited in the wild.

**How severe is CVE-2026-23748?** Low severity, with a CVSS score of 3.7, published 26 February 2026.

**Which products and versions are affected?** Golioth Firmware SDK 0.10.0 to 0.21.x.

**Is there a fix for CVE-2026-23748?** A patch was published on 2025-12-17: Version 0.22.0 released with fix Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-23748 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-23748?** Check whether you run Golioth Firmware SDK at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

An integer underflow vulnerability exists in the LightDB State string parsing component of the Golioth Firmware SDK. When the `on_payload` function processes a string payload with a `payload_size` less than 2, the calculation for `nbytes` (intended to strip quotation marks) results in a `size_t` underflow. This leads to a large value being passed to `memcpy()`, causing an out-of-bounds read from the network buffer and a subsequent device crash. The vulnerability is reachable because `golioth_payload_is_null()` fails to block payloads with a size of 1. The issue is fixed in version 0.22.0 and commit d7f55b38.

## Affected products

- Golioth Firmware SDK 0.10.0 to 0.21.x

## Timeline

- 2026-02-26: advisory: Initial disclosure by VulnCheck and SecMate
- 2026-02-26: disclosed
- 2025-12-17: patched: Version 0.22.0 released with fix

## References

- [https://blog.secmate.dev/posts/golioth-vulnerabilities-disclosure/](https://blog.secmate.dev/posts/golioth-vulnerabilities-disclosure/)
- [https://github.com/golioth/golioth-firmware-sdk/commit/d7f55b380d8be8b29bd101ce06e421af2e88c12b](https://github.com/golioth/golioth-firmware-sdk/commit/d7f55b380d8be8b29bd101ce06e421af2e88c12b)
- [https://github.com/golioth/golioth-firmware-sdk/releases/tag/v0.22.0](https://github.com/golioth/golioth-firmware-sdk/releases/tag/v0.22.0)
- [https://secmate.dev/disclosures/SECMATE-2025-0016](https://secmate.dev/disclosures/SECMATE-2025-0016)
- [https://www.vulncheck.com/advisories/golioth-firmware-sdk-lightdb-state-out-of-bounds-read](https://www.vulncheck.com/advisories/golioth-firmware-sdk-lightdb-state-out-of-bounds-read)

## Related threats

- [Golioth Firmware SDK out-of-bounds read in blockwise transfer path](https://junglewise.ai/threats/cve-2026-23749-golioth-firmware-sdk-out-of-bounds-read-in-blockwise-transfer)
- [Golioth Firmware SDK stack buffer overflow in Payload Utils](https://junglewise.ai/threats/cve-2026-23747-golioth-firmware-sdk-stack-buffer-overflow-in-payload-utils)