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Rocky Linux 9.6 [TuxCare] Security Update: kernel / kernel-64k / kernel-64k-core / kernel-64k-debug / etc Multiple Vulnerabilities (ALMALINUX9.6:CLSA-2026:1783793262)
high Nessus Plugin ID 359559
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Synopsis
The Rocky Linux host is missing one or more security updates.Description
The Rocky Linux 9.6 host has packages installed that are affected by multiple vulnerabilities as referenced in the TuxCare ALMALINUX9.6:CLSA-2026:1783793262 advisory.- In the Linux kernel, the following vulnerability has been resolved: rtmutex: Use waiter::task instead of current in remove_waiter() remove_waiter() is used by the slowlock paths, but it is also used for proxy- lock rollback in rt_mutex_start_proxy_lock() when invoked from futex_requeue(). In the latter case waiter::task is not current, but remove_waiter() operates on current for the dequeue operation. That results in several problems: 1) the rbtree dequeue happens without waiter::task::pi_lock being held 2) the waiter task's pi_blocked_on state is not cleared, which leaves a dangling pointer primed for UAF around.
3) rt_mutex_adjust_prio_chain() operates on the wrong top priority waiter task Use waiter::task instead of current in all related operations in remove_waiter() to cure those problems. [ tglx: Fixup rt_mutex_adjust_prio_chain(), add a comment and amend the changelog ] (CVE-2026-43499)
- In 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. (CVE-2026-46242)
Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.
Solution
Update the affected packages based on the guidance in TuxCare advisory ALMALINUX9.6:CLSA-2026:1783793262.See Also
Plugin Details
Severity: High
ID: 359559
File Name: tuxcare_rocky_linux_9.6_CLSA-2026-1783793262.nasl
Version: 1.4
Type: Local
Published: 10/1/2026
Updated: 10/22/2026
Supported Sensors: Nessus Agent, Continuous Assessment, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus
Risk Information
VPR
Risk Factor: Critical
Score: 9.5
Percentile: 99.87
Vendor
Vendor Severity: Important
CVSS v2
Risk Factor: Medium
Base Score: 6.8
Temporal Score: 5.9
Vector: CVSS2#AV:L/AC:L/Au:S/C:C/I:C/A:C
CVSS Score Source: CVE-2026-46242
CVSS v3
Risk Factor: High
Base Score: 7.8
Temporal Score: 7.5
Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Temporal Vector: CVSS:3.0/E:H/RL:O/RC:C
Vulnerability Information
Required KB Items: Host/local_checks_enabled, Host/cpu, Host/RockyLinux/release, Host/RockyLinux/rpm-list, Host/OS/extended-third-party
Exploit Available: true
Exploit Ease: Exploits are available
Patch Publication Date: 7/11/2026
Vulnerability Publication Date: 5/21/2026
Reference Information
CVE: CVE-2026-43499, CVE-2026-46242
CLSA: 2026:1783793262