Bug 2535166 (CVE-2026-89988)

Summary: CVE-2026-89988 kernel: kprobes: Protect kprobe_blacklist with RCU
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in the kprobes component of the Linux kernel. A local attacker could potentially exploit a use-after-free vulnerability when a module is unloaded concurrently with a call to `__within_kprobe_blacklist()`. This could lead to dereferencing freed memory, potentially causing system instability or a denial of service.
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Description OSIDB Bzimport 2026-09-16 11:05:16 UTC 
In the Linux kernel, the following vulnerability has been resolved:

kprobes: Protect kprobe_blacklist with RCU

__within_kprobe_blacklist() traverses kprobe_blacklist without holding
kprobe_mutex. When a module is unloaded, kprobe_remove_area_blacklist()
removes blacklist entries and immediately frees them with kfree().
A concurrent call to within_kprobe_blacklist() can therefore dereference
freed memory.

Furthermore, within_kprobe_blacklist() can be called in atomic or
non-preemptible contexts where the sleeping kprobe_mutex cannot be taken.

Protect kprobe_blacklist with RCU. Use guard(rcu)() and
list_for_each_entry_rcu() for traversal, list_add_tail_rcu() for
insertions, list_del_rcu() for deletions, and kfree_rcu() to reclaim
entries safely after a grace period.
Comment 1 Keith Grant 2026-09-16 21:12:26 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89988.mbox