CVE-2026-98013: Linux kernel · net/sched: fq_pie: clamp quantum in change path
Affects Linux kernelSource CVE Database V5
Not known to be exploited · fixed in ff4f3a0f3abd2ded467931d7da7984a68a768e0b : patch Linux kernel soon.
Data as of 26 Oct 2026, 16:39 UTC
Rated High by Threat Radar's AI analysis · CVSS not yet scored by NVD
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in ff4f3a0f3abd2ded467931d7da7984a68a768e0b, f90fe65b977e7aa9eb302230a09eb18f8c32ceaa, c11e3a39807eb5a200445ae9082843ab86800415 +5
Exploitation evidence
Disclosed: evidence found.
CVE published 25 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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AI-suggested
The vulnerability has been fixed in the Linux kernel by adding a clamp to the quantum value in fq_pie_change(), ensuring it is at least 256. Users should upgrade to a Linux kernel version that includes the fix (commits referenced). No additional mitigation is required if running a fixed kernel version. Systems running version 5.6 with CONFIG_NET_SCH_FQ_PIE enabled should be updated promptly.
Description
CVE-2026-98013 is a vulnerability in the Linux kernel's fq_pie queuing discipline where the quantum value accepted from userspace is not properly clamped. This allows a crafted configuration to cause a soft lockup or denial of service by making the deficit-refill loop spin excessively under the qdisc lock. The issue affects Linux kernel version 5.6 and requires the CONFIG_NET_SCH_FQ_PIE option enabled and CAP_NET_ADMIN privileges. The vulnerability has been fixed by adding a minimum quantum clamp of 256, matching the fq_codel_change() implementation.
References
- git.kernel.org/stable/c/ff4f3a0f3abd2ded467931d7da7984a68a768e0b (opens in a new tab)
- git.kernel.org/stable/c/749aaebc1eb92ce2f38fd3caf68a2f99686d84ef (opens in a new tab)
- git.kernel.org/stable/c/8fd98e56c41f79278eeb67512c28d7abc175bcf4 (opens in a new tab)
- git.kernel.org/stable/c/215df1e953ae72a09d425ec188e054058ae23dc9 (opens in a new tab)
- git.kernel.org/stable/c/f90fe65b977e7aa9eb302230a09eb18f8c32ceaa (opens in a new tab)
- git.kernel.org/stable/c/c11e3a39807eb5a200445ae9082843ab86800415 (opens in a new tab)
- git.kernel.org/stable/c/6655b56e2801008566c594ef231f6c7b3f716c61 (opens in a new tab)
- git.kernel.org/stable/c/4864f58c53eb47257d55e01f47d4a9f355f7f970 (opens in a new tab)