CVE-2026-15449 TOCTOU double copyin in illumos dld ioctl handling causes kernel heap corruption
A race condition in illumos kernel ioctl handling allows local attackers to corrupt kernel memory, causing system panics or potential code execution.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-15449?
CVE-2026-15449 is a medium-severity vulnerability in OmniOS, published on 16 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
A time-of-check to time-of-use (TOCTOU) flaw in the illumos data-link pseudo-driver (dld) affects handling of the DLDIOC_GETMACPROP and DLDIOC_SETMACPROP ioctls on /dev/dld. drv_ioc_prop_common() in usr/src/uts/common/io/dld/dld_drv.c copies the dld_ioc_macprop_t ioctl header in once to read its pr_valsize field, sizes and allocates a kernel heap buffer from that value, and then copies the full request in a second time from the same unprivileged user address. A concurrent thread can enlarge pr_valsize between the two copyins, so the second copyin and the subsequent property handling write beyond the end of the undersized allocation and corrupt the kernel heap. An unprivileged local user, including one confined to a non-global zone that owns a datalink, can trigger this to panic the system. The resulting kernel heap corruption may be usable for further compromise.
Which versions are affected by CVE-2026-15449?
How do I fix CVE-2026-15449?
No fix has been published for CVE-2026-15449 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-15449 being exploited?
There is no known exploitation of CVE-2026-15449 in the wild and no public exploit code.
Sources
Also known as GHSA-5jqp-7hrf-w792.