illumos Data-Link Pseudo-Driver dld_drv.c drv_ioc_prop_common toctou

Summaryinfo

A vulnerability labeled as very critical has been found in illumos. This affects the function drv_ioc_prop_common of the file usr/src/uts/common/io/dld/dld_drv.c of the component Data-Link Pseudo-Driver. Such manipulation leads to toctou. This vulnerability is traded as CVE-2026-15449. An attack has to be approached locally. There is no exploit available.

Detailsinfo

A vulnerability was found in illumos (the affected version unknown) and classified as very critical. Affected by this issue is the function drv_ioc_prop_common of the file usr/src/uts/common/io/dld/dld_drv.c of the component Data-Link Pseudo-Driver. The manipulation with an unknown input leads to a toctou vulnerability. Using CWE to declare the problem leads to CWE-367. The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check. This can cause the product to perform invalid actions when the resource is in an unexpected state. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is available at illumos.topicbox.com. This vulnerability is handled as CVE-2026-15449 since 07/10/2026. The exploitation is known to be easy. Local access is required to approach this attack. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 07/16/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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• illumos

CPE 2.3info

• 🔒

CPE 2.2info

• 🔒

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If you want to get best quality of vulnerability data, you may have to visit VulDB.

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