CVE-2026-72482: gpib: fix double decrement of descriptor_busy in command_ioctl()
In the Linux kernel, the following vulnerability has been resolved:
gpib: fix double decrement of descriptorbusy in commandioctl()
commit d1857f8296dc ("gpib: fix use-after-free in IO ioctl handlers") introduced a descriptorbusy reference counter to pin struct gpibdescriptor across IO ioctl operations. In commandioctl(), the error path inside the loop decrements descriptorbusy and breaks, but execution then falls through to the unconditional decrement after the loop, underflowing the counter to -1.
This re-enables the use-after-free that the original fix was meant to prevent: a concurrent closedevioctl() sees descriptorbusy == 0 on an actively-used descriptor and frees it.
Remove the early decrement from the error path. The post-loop decrement already handles all exit paths, matching the correct pattern used in readioctl() and writeioctl().
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
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Remove the early decrement of descriptor_busy from the error path inside the command_ioctl() loop; retain the unconditional post-loop decrement so all exit paths decrement the counter exactly once.
Linux kernel gpib command_ioctl() descriptor_busy decrement in the loop error path = removed
Event History
Frequently Asked Questions
What is the severity of CVE-2026-72482?
The severity of CVE-2026-72482 is rated at 43, indicating a moderate risk associated with this vulnerability.
How do I fix CVE-2026-72482?
To fix CVE-2026-72482, update to the latest version of the Linux kernel that includes the patch for this vulnerability.
What specific issue does CVE-2026-72482 address?
CVE-2026-72482 addresses a double decrement of descriptor_busy in the command_ioctl() function, leading to a use-after-free vulnerability.
In which version of the Linux kernel was CVE-2026-72482 resolved?
CVE-2026-72482 was resolved with the commit d1857f8296dc in the Linux kernel.
What components are affected by CVE-2026-72482?
The gpib subsystem within the Linux kernel is affected by CVE-2026-72482 due to issues in IO ioctl handlers.