# CVE-2026-15690: open62541 null pointer dereference in responseReadNamespacesArray

Source: https://junglewise.ai/threats/cve-2026-15690-open62541-null-pointer-dereference-in-responsereadnamespacesarray  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-14. Updated: 2026-07-14  
License: CC BY 4.0 with a link back

CVE-2026-15690 · Severity: low · CVSS 3.1 · Published 2026-07-14

open62541 is an open-source implementation of the OPC UA industrial communication protocol used in manufacturing and automation. A vulnerability in the client library allows a malicious server to crash any application connecting to it. This results in a denial-of-service, potentially disrupting industrial monitoring or control operations that rely on these connections.

## Quick answers

**Is CVE-2026-15690 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-15690 being exploited in the wild.

**How severe is CVE-2026-15690?** Low severity, with a CVSS score of 3.1, published 14 July 2026.

**Which products and versions are affected?** open62541 open62541 up to 1.5.5.

**Is there a fix for CVE-2026-15690?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-15690 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-15690?** Check whether anything you run is named in the advisory. 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

A null pointer dereference exists in the `responseReadNamespacesArray` function within `src/client/ua_client_connect.c`. When a client automatically reads the `Server_NamespaceArray` after session activation, a malicious server can return a successful `ReadResponse` with a `resultsSize` of 0 but an encoded empty array. The client library decodes this as `UA_EMPTY_ARRAY_SENTINEL` (0x01) and subsequently attempts to dereference the first element of the results array without verifying the size. This leads to an invalid memory read and a deterministic process crash. The attack is reachable remotely during the standard OPC UA handshake but requires a high level of complexity to exploit.

## Affected products

- open62541 open62541 up to 1.5.5

## Timeline

- 2026-07-14: advisory: NVD publication date
- 2026-07-14: disclosed: VulDB entry created

## References

- [https://github.com/open62541/open62541/](https://github.com/open62541/open62541/)
- [https://github.com/open62541/open62541/issues/8104](https://github.com/open62541/open62541/issues/8104)
- [https://vuldb.com/cve/CVE-2026-15690](https://vuldb.com/cve/CVE-2026-15690)
- [https://vuldb.com/submit/855996](https://vuldb.com/submit/855996)
- [https://vuldb.com/vuln/378237](https://vuldb.com/vuln/378237)
- [https://vuldb.com/vuln/378237/cti](https://vuldb.com/vuln/378237/cti)