# CVE-2026-54436: QNX io-char heap buffer overflow in DCMD_CHR_WAITINFO handler

Source: https://junglewise.ai/threats/cve-2026-54436-heap-based-buffer-overflow-in-the-io-char-library-s-dcmd-chr  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-10. Updated: 2026-11-10  
License: CC BY 4.0 with a link back

CVE-2026-54436 · Severity: high · CVSS 7.4 · Published 2026-11-10

A heap buffer overflow exists in QNX's io-char library, which handles character device I/O operations in real-time embedded systems. An attacker with local access to the system could exploit this vulnerability to execute arbitrary code, corrupt data, or crash the character device driver, potentially compromising system stability or enabling privilege escalation.

Vendors: [QNX](https://junglewise.ai/threats/vendors/qnx).

## Quick answers

**Is CVE-2026-54436 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-54436 being exploited in the wild.

**How severe is CVE-2026-54436?** High severity, with a CVSS score of 7.4, published 10 November 2026.

**Which products and versions are affected?** QNX io-char.

**Is there a fix for CVE-2026-54436?** 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-2026-54436 attacked?** It is attacked with local access, in a software library.

**Am I affected by CVE-2026-54436?** Check whether you run QNX Io-Char. 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

The vulnerability is a heap-based buffer overflow in the DCMD_CHR_WAITINFO devctl() handler of the io-char library. It requires local access to trigger the overflow via a malformed devctl() call. Successful exploitation allows data corruption, arbitrary code execution, or denial of service on the affected device driver.

## Affected products

- QNX io-char

## Timeline

- 2026-11-10: disclosed

## References

- [https://support.blackberry.com/pkb/s/article/141341](https://support.blackberry.com/pkb/s/article/141341)