What’s Vulnerable › Vulnerabilities

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

• Severity: unknown
• 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: 2026-10-18 · updated 2026-10-30

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.

Affected products

• Linux: 2.6.34 — 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/3b0f604df9e2b9a456f1ae5266a439998c4c8826
• https://git.kernel.org/stable/c/3f968dcdf018861129f97910fa7bd680d939a9b0
• https://git.kernel.org/stable/c/526fac219e8b7d3369b43026bd0a1df51b811cd4
• https://git.kernel.org/stable/c/6745fa65f4115045431c0c15610e876855a04625
• https://git.kernel.org/stable/c/7a39c732a22ec4a369af9e19fbe3d666ec83eec4
• https://git.kernel.org/stable/c/985a568171e7bdba6dcde3420d0e5bb515813457
• https://git.kernel.org/stable/c/ab9ed9faa67bf67383ff7e1479655e232a843c2b
• https://git.kernel.org/stable/c/e29e819cacfb4e3cd56d41eb704ab4718d6d2915

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