# CVE-2026-102720: Memory corruption in eclipse-threadx/netxduo

> A DHCP client flaw allows remote attackers to read memory past buffer boundaries via crafted DHCP offers, potentially disclosing sensitive data or causing crashes.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 29 Sep 2026
- **Updated:** 29 Sep 2026
- **Also known as:** GHSA-8hj5-p46x-5h28, GHSA-rw53-r2p7-qgmf

## What is CVE-2026-102720?

CVE-2026-102720 is a medium-severity memory corruption vulnerability in eclipse-threadx/netxduo, published on 29 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A DHCP server, or anyone on the LAN who answers a DISCOVER first, can make the client read about a

kilobyte past the end of the received message.

The option walk keeps a pointer and an offset in step, and the only bound check uses the offset:

```c

/* addons/dhcp/nxd_dhcp_client.c:7538, 7572 */

while (i < length - 1)

{

    ...
    size = *(++data);      /* data moves 1: type -> length byte */
    data += size + 1;      /* data moves size + 1 more          */
    i += size + 1;         /* i moves only size + 1             */

}

```

A TLV option occupies size + 2 bytes. `data` is advanced by size + 2 in total, `i` by size + 1, so

the offset falls one byte behind the real read position for every option the walk skips. After

enough skipped options the check `i < length - 1` still holds while `data` is already past the end

of the message, and the subsequent read of the type and length bytes comes from whatever follows.

A single OFFER carrying a long run of skippable options is enough:

```

ERROR: AddressSanitizer: heap-buffer-overflow

READ of size 1 at 0x61b000000794 thread T5

    #0 _nx_dhcp_search_buffer     addons/dhcp/nxd_dhcp_client.c:7541
    #1 _nx_dhcp_get_option_value  addons/dhcp/nxd_dhcp_client.c:7082

0x61b000000794 is located 164 bytes to the right of 1648-byte region

```

A well formed OFFER through the same path is handled normally, the client records the offer and

moves to REQUESTING, so the difference is the option layout rather than the harness.

The read runs in the DHCP client thread while the client is still unconfigured, so it happens on

every boot in reach of a hostile DHCP responder. The values read are used to configure the

interface, which is how the disclosed bytes become observable.

Advance `i` by size + 2, or derive the bound from `data` rather than keeping a second counter.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-102720?


## How do I fix CVE-2026-102720?

No fix has been published for CVE-2026-102720 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-102720 being exploited?

There is no known exploitation of CVE-2026-102720 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-102720 and fix it if it is affected.

What it is: CVE-2026-102720 is a medium-severity memory corruption vulnerability in eclipse-threadx/netxduo, published on 29 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-102720 in the wild and no public exploit code.

Affected product: eclipse-threadx/netxduo. 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-2026-102720/ (Markdown: https://insights.sbomify.com/CVE-2026-102720/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-102720
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-102720
- OSV: https://osv.dev/vulnerability/CVE-2026-102720

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-102720/
Summaries are generated and may contain mistakes; the official description above is the record.