Excessive Iteration in Linux kernel - CVE-2026-98427

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Main Vulnerability Database Vulnerabilities #VU155883

Excessive Iteration in Linux kernel - CVE-2026-98427

Published: October 15, 2026


Vulnerability identifier: #VU155883
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-98427
CWE-ID: CWE-834
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to excessive iteration in the shared CoDel codel_dequeue() function when processing queued packets with a control-law increment that rounds down to zero or an excessive drop backlog after an idle gap. A local user can generate a UDP flood through an affected queueing configuration to cause a denial of service.

The reported reproducer uses a very small CoDel interval beneath a low-rate token bucket filter on the loopback interface. Packet dropping holds the queueing discipline lock long enough to trigger a kernel soft lockup.


Affected software

Linux kernel
Ubuntu
linux (Ubuntu package)
linux-aws (Ubuntu package)
linux-gcp (Ubuntu package)
linux-oracle (Ubuntu package)
linux-ibm (Ubuntu package)
linux-hwe-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)

How to mitigate CVE-2026-98427

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux (Ubuntu package) - update to 7.0.0-42.42
linux-aws (Ubuntu package) - update to 7.0.0-1016.17
linux-gcp (Ubuntu package) - update to 7.0.0-1016.18
linux-oracle (Ubuntu package) - update to 7.0.0-1015.16
linux-ibm (Ubuntu package) - update to 7.0.0-1017.17
linux-hwe-7.0 (Ubuntu package) - update to 7.0.0-42.42~24.04.1
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1017.17

External References

Related Security Bulletins