Quick answers
- Is CVE-2026-90589 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-90589 being exploited in the wild.
- How severe is CVE-2026-90589?
- Medium severity, with a CVSS score of 5.5, published 9 November 2026.
- Which products and versions are affected?
- Zephyr Zephyr OS.
- Is there a fix for CVE-2026-90589?
- 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-2026-90589 attacked?
- It is attacked with local access, in an operating system.
- Am I affected by CVE-2026-90589?
- Check whether you run Zephyr OS. 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
When CONFIG_THREAD_STACK_MEM_MAPPED is enabled, thread stacks are guarded by memory-mapped pages. The k_thread_abort_cleanup() function has two code paths: self-abort (which correctly unmaps the stack) and abort-by-another-thread (which incorrectly fails to unmap the target thread's stack). On x86 targets with memory-mapped stacks enabled and unprivileged userspace, an attacker can repeatedly create and abort threads to leak kernel virtual address space until k_mem_map_phys_guard() fails, causing thread creation to fault in kernel mode.
Affected products
- Zephyr Zephyr OS
Timeline
- 2026-11-09: disclosed