SB20260720250 - Uncontrolled Recursion in Linux kernel sched

Description

This security bulletin contains information about 1 vulnerability.

1) Uncontrolled Recursion (CVE-ID: CVE-2026-63983)

CWE-ID: CWE-674 - Uncontrolled Recursion

CVSSv4: 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]

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

The vulnerability exists due to uncontrolled recursion in netem packet duplication handling in the netem qdisc when processing duplicated packets through a qdisc tree containing another netem instance. A local user can trigger packet duplication to cause a denial of service.

Exploitation can exhaust stack or memory when packet duplication is enabled and duplicated packets are re-enqueued through another netem in the tree.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/1a298a514ce766c6d0c232991a390fec67af81ad
• https://git.kernel.org/stable/c/9552b11e3edabc97cfcd9f29103d5afbce7ae183
• https://git.kernel.org/stable/c/cfb2616042767ab31260d4f39190c381bec8b12e