CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HIn the Linux kernel, the following vulnerability has been resolved: eventpoll: fix ep_remove struct eventpoll / struct file UAF ep_remove() (via ep_remove_file()) cleared file->f_ep under file->f_lock but then kept using @file inside the critical section (is_file_epoll(), hlist_del_rcu() through the head, spin_unlock). A concurrent __fput() taking the eventpoll_release() fastpath in that window observed the transient NULL, skipped eventpoll_release_file() and ran to f_op->release / file_free(). For the epoll-watches-epoll case, f_op->release is ep_eventpoll_release() -> ep_clear_and_put() -> ep_free(), which kfree()s the watched struct eventpoll. Its embedded ->refs hlist_head is exactly where epi->fllink.pprev points, so the subsequent hlist_del_rcu()'s "*pprev = next" scribbles into freed kmalloc-192 memory. In addition, struct file is SLAB_TYPESAFE_BY_RCU, so the slot backing @file could be recycled by alloc_empty_file() -- reinitializing f_lock and f_ep -- while ep_remove() is still nominally inside that lock. The upshot is an attacker-controllable kmem_cache_free() against the wrong slab cache. Pin @file via epi_fget() at the top of ep_remove() and gate the critical section on the pin succeeding. With the pin held @file cannot reach refcount zero, which holds __fput() off and transitively keeps the watched struct eventpoll alive across the hlist_del_rcu() and the f_lock use, closing both UAFs. If the pin fails @file has already reached refcount zero and its __fput() is in flight. Because we bailed before clearing f_ep, that path takes the eventpoll_release() slow path into eventpoll_release_file() and blocks on ep->mtx until the waiter side's ep_clear_and_put() drops it. The bailed epi's share of ep->refcount stays intact, so the trailing ep_refcount_dec_and_test() in ep_clear_and_put() cannot free the eventpoll out from under eventpoll_release_file(); the orphaned epi is then cleaned up there. A successful pin also proves we are not racing eventpoll_release_file() on this epi, so drop the now-redundant re-check of epi->dying under f_lock. The cheap lockless READ_ONCE(epi->dying) fast-path bailout stays.
Multiple vulnerabilities have been discovered in the Linux kernel of Ubuntu. Some of these vulnerabilities allow for privilege escalation, data confidentiality compromise, and data integrity compromise. These vulnerabili…
Multiple vulnerabilities have been discovered in the Linux kernel of Ubuntu. Some of these vulnerabilities allow for remote denial of service, privilege escalation, and an unspecified security issue. These vulnerabilitie…
Multiple vulnerabilities have been discovered in the Linux kernel of Ubuntu. Some of these vulnerabilities allow for privilege escalation, data confidentiality breaches, and data integrity compromise. These vulnerabiliti…
Multiple vulnerabilities have been discovered in the SUSE Linux kernel. Several of these vulnerabilities can lead to data confidentiality and integrity breaches, as well as the circumvention of security policies and deni…
Multiple vulnerabilities have been discovered in the SUSE Linux kernel. Some of these vulnerabilities allow for data confidentiality and integrity breaches, as well as bypassing security policies and causing denial of se…
Multiple vulnerabilities have been discovered in the Linux kernel of Ubuntu. Some of these vulnerabilities allow for privilege escalation, data confidentiality breaches, and denial of service attacks. The vulnerabilities…
Multiple vulnerabilities have been discovered in Red Hat's Linux kernel. These vulnerabilities can lead to arbitrary code execution, privilege escalation, and a denial-of-service attack. Red Hat has released security adv…
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A proof-of-concept exploit for a Linux kernel vulnerability, dubbed ‘Bad Epoll,’ has been released, allowing unprivileged processes to gain root access on various devices. The vulnerability stems from a race condition wi…
A newly discovered Linux kernel vulnerability, dubbed "Bad Epoll" (CVE-2026-46242), allows unprivileged users to gain root access on systems, including Android devices. The flaw, a "use-after-free" bug, was identified by…
