CVE-2026-80994 Linux CVE debrief

Who should care

Linux kernel developers and maintainers, Open vSwitch users and administrators, and security teams should assess exposure and prioritize patching. They should review and apply the provided kernel patches to fix the vulnerability, monitor system logs for potential exploitation attempts, and consider implementing additional security controls, such as network segmentation and access controls.

Why it matters

A use-after-free vulnerability in the Linux kernel's Open vSwitch implementation could lead to a system crash. Linux kernel developers and maintainers, as well as Open vSwitch users and administrators, should assess exposure and prioritize patching.

• Potential system crash due to use-after-free vulnerability
• Need to verify and apply kernel patches to fix the vulnerability
• Monitoring system logs for potential exploitation attempts is recommended

Technical summary

The vulnerability exists in the Linux kernel's Open vSwitch implementation. The `ovs_flow_cmd_fill_info` function may access the `flow->mask` pointer after it has been freed, potentially leading to a crash. This occurs when processing the `CMD_DEL` command. The issue arises from the `ovs_flow_cmd_fill_info` function using the `flow->mask` pointer after it has been freed. The `ovs_flow_tbl_remove` function must be called after the `ovs_flow_cmd_fill_info` function to avoid this race condition. Linux kernel developers and maintainers, as well as Open vSwitch users and administrators, should assess exposure and prioritize patching.

Defensive priority

Medium

Recommended defensive actions

• Review and apply the provided kernel patches to fix the vulnerability
• Monitor system logs for potential exploitation attempts
• Consider implementing additional security controls, such as network segmentation and access controls
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The vulnerability was reported by Trend Micro's Zero Day Initiative as ZDI-CAN-32042. The issue is caused by the `ovs_flow_cmd_fill_info` function using the `flow->mask` pointer after it has been freed. The `ovs_flow_tbl_remove` function must be called after the `ovs_flow_cmd_fill_info` function to avoid this race condition. The vulnerability exists in the Linux kernel's Open vSwitch implementation, and Linux kernel developers and maintainers, as well as Open vSwitch users and administrators, should assess exposure and prioritize

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.