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CVE-2026-89988: kprobes: Protect kprobe_blacklist with RCU

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-16 · updated 2026-10-30

Description

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.

Affected products

• Linux: 3.16 — fixed in 7.3

How to fix

Upgrade to a fixed version: Linux 7.3. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/0c4256196b3a105307e2235fbfd85e768bbcdd0f
• https://git.kernel.org/stable/c/3fb8386682ef4d0858c38bf0d8d8a47ba171fa23
• https://git.kernel.org/stable/c/518d9b5568bb06f86e4434f7a30faa9612ea91ad
• https://git.kernel.org/stable/c/5d97a13defc648c64d138145ace429b6a3d08943
• https://git.kernel.org/stable/c/5da247e4d1e8661d4d6f997101d59967e8994e32
• https://git.kernel.org/stable/c/630ed8734a02b992e8a97538179c2ece42c5210f
• https://git.kernel.org/stable/c/6e62cf983a2bd547e6bbd3f935539233e5f97f8f
• https://git.kernel.org/stable/c/8f406205003f741225f620f0e357ca0de71d45e3

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