CVE-2026-80977 Linux CVE debrief

Who should care

Linux kernel maintainers, Linux distribution maintainers, Open vSwitch users, and administrators of systems utilizing the Linux kernel should assess their exposure to this vulnerability and verify the presence of the fix.

Why it matters

CVE-2026-80977 is a Linux kernel vulnerability that requires verification of exposure and fix presence, particularly in Open vSwitch environments.

• Verification of Linux kernel versions and Open vSwitch configurations is necessary to ensure the fix is applied
• Potential inconsistencies in zerocopy state handling could lead to unexpected behavior or crashes
• Administrators should monitor for issues related to zerocopy state handling in the Linux kernel

Technical summary

The Linux kernel vulnerability (CVE-2026-80977) relates to the handling of zerocopy state in the `skb_tx_error()` function. When a cloned skb is passed to this function, it could potentially modify shared zerocopy state. The issue arises in Open vSwitch when a non-last `OVS_ACTION_ATTR_RECIRC` action is executed. The code now skips modifying the zerocopy state for cloned skbs to ensure consistency and accuracy.

Defensive priority

Linux kernel maintainers and users should assess exposure and verify the presence of the fix, particularly in environments utilizing Open vSwitch.

Recommended defensive actions

• Review Linux kernel configurations and versions to ensure the fix is applied
• Assess Open vSwitch usage and verify that updates have been applied
• Monitor for potential issues related to zerocopy state handling in the Linux kernel
• Perform a thorough review of system logs to detect any anomalies related to the Linux kernel
• Verify the integrity of the Linux kernel's network stack implementation
• Update documentation to reflect changes in zerocopy state handling for cloned skbs
• Conduct a risk assessment to identify potential vectors of exploitation in the environment

Evidence notes

The CVE record and associated source references provide details on the vulnerability and its resolution. However, the impact and affected versions require further verification from official sources. Linux kernel maintainers and users should assess exposure and verify the presence of the fix, particularly in environments utilizing Open vSwitch. The fix involves skipping modification of zerocopy state for cloned skbs to ensure consistency and accuracy. This change prevents potential inconsistencies that could lead to unexpected behavior

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.