CVE-2026-98775
Description
In the Linux kernel, the following vulnerability has been resolved:
nitro_enclaves: fix use-after-free on SLOT_ALLOC failure
When ne_create_vm_ioctl() fails the SLOT_ALLOC request after
anon_inode_getfile() has succeeded, the error path calls
fput(enclave_file) and then frees ne_enclave.
In normal userspace context, fput() defers the final __fput() via
task_work. ne_enclave_release() therefore runs after ne_enclave has
already been freed and dereferences ne_enclave->slot_uid, causing a
use-after-free: KASAN: slab-use-after-free in ne_enclave_release.
The enclave has no slot allocated and is not yet linked into the
enclaves list on this error path, so ne_enclave_release() is expected
to return early when slot_uid is zero. However, reading slot_uid
already accesses the freed object.
Clear enclave_file->private_data before fput() on the error path.
ne_enclave_release() then returns immediately when private_data is
NULL, leaving the ioctl error path as the sole owner of ne_enclave.
This is safe because the file has not been fd_install()'d yet.
Tested on an AWS EC2 m5.2xlarge with CONFIG_KASAN=y. Without the
patch, the reproducer triggers a KASAN slab-use-after-free on every
SLOT_ALLOC failure. With the patch, no KASAN report is produced and
the SLOT_ALLOC error is still returned. Normal enclave creation and
teardown are unaffected.
EPSS (Exploit Prediction Scoring System)
EPSS (Exploit Prediction Scoring System)
Prevede la probabilità di sfruttamento basata su intelligence sulle minacce e sulle caratteristiche della vulnerabilità.