Is there a public exploit for CVE-2026-90586?

No public exploit for CVE-2026-90586 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

How severe is CVE-2026-90586?

CVE-2026-90586 scores CVSS 7.8 (v3.1), rated high.

What does CVE-2026-90586 affect?

CVE-2026-90586 affects zephyrproject Zephyr.

7.8 High

The Xtensa MMU userspace port never initialized the per-thread page-table pointer thread->arch.ptables during thread setup, while…

CVE-2026-90586

The Xtensa MMU userspace port never initialized the per-thread page-table pointer thread->arch.ptables during thread setup, while archmemdomainthreadadd() in arch/xtensa/core/ptables.c uses a non-NULL value of that field as its "this thread is migrating from another memory domain" predicate. For a thread whose struct kthread backing memory is not zeroed, the field holds stale data and the kernel takes the migration branch, passing that stale value to resetregion() as the base of a level-1 page table. The equivalent field on x86 is explicitly cleared in zx86userspacepreparethread() for exactly this reason; the Xtensa port adopted the predicate without the initialization. The condition is reachable from an unprivileged user-mode thread on a build with CONFIGXTENSAMMU, CONFIGUSERSPACE and dynamically allocated kernel objects. kobjectalloc(KOBJTHREAD) is a system call and allocates the thread object from the caller's resource pool without zeroing it, and the kthreadcreate() verifier accepts such an object while forcing the KUSER option, so the migration branch is taken whenever the recycled heap bytes at that offset are non-zero. Because a user thread can also allocate, fill and free…

Assessment

CVSS: 7.8 (v3.1)
Severity: High
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 9 November 2026
Last updated: 9 November 2026
Affected: zephyrproject · Zephyr
Assigner: zephyr

CVSS vectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

At the source

EUVD (ENISA)

References

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