ZDI-26-571: Linux Kernel Net Scheduler Packet Classifier API Use-After-Free Local Privilege Escalation Vulnerability
Admiralty grading (A–F · 1–6)
Source reliability
- A Completely reliable
- B Usually reliable
- C Fairly reliable
- D Not usually reliable
- E Unreliable
- F Cannot be judged
Information credibility
- 1 Confirmed
- 2 Probably true
- 3 Possibly true
- 4 Doubtful
- 5 Improbable
- 6 Cannot be judged
NATO Admiralty (AJP-2.1) grades confidence, independent of the risk score. Cross-source corroboration isn't tracked for non-CVE news, so single-source items are capped at a lower credibility number; a low number does not imply low quality.
Key metrics
- CVSS
- 9.8
- EPSS
- 1%
Key insight
The flaw allows local attackers to escalate privileges in the Linux kernel and affects unpatched Ubuntu systems.
Description
CVE-2026-64530 is a use-after-free vulnerability in the Linux kernel's Net Scheduler Packet Classifier API. A local attacker must first be able to execute low-privileged code to exploit the flaw and escalate privileges. The ZDI has assigned a CVSS score of 8.8. Linux kernel installations are affected; active exploitation is not currently known.
Risk score
- cvss base
- 98.00
- kev bonus
- 0.00
- epss bonus
- 0.00
- poc bonus
- 15.00
- raw before weight
- 113.00
- industry weight
- 1.10
- freshness factor
- 0.50
- exploitability factor
- 1.00
- days old
- 30.00
- vendor mismatch penalty
- 0.00
Path: operational
MITRE ATT&CK mapping
1 TTPProcedure details
| Technique | Tactic | Procedure | Conf. | Source |
|---|---|---|---|---|
| T1068 Exploitation for Privilege Escalation | Privilege Escalation | The attacker exploits a use-after-free vulnerability in the Linux kernel's net scheduler packet classifier API (CVE-2026-64530) after obtaining low-privileged code execution, triggering the bug to execute arbitrary code with elevated privileges. | high | llm |