CVE-2026-74398

Received Received - Intake

Use-After-Free in Linux Kernel IPv6 Address Configuration

Publication date: 2026-08-15

Last updated on: 2026-08-17

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: ipv6: addrconf: bail out of dad_failure when state is no longer POSTDAD addrconf_dad_failure() transitions ifp->state from DAD to POSTDAD via addrconf_dad_end(), which drops ifp->lock on return. The lock is re-acquired after net_info_ratelimited(). A concurrent ipv6_del_addr() can take the lock in that window, set ifp->state to DEAD and run list_del_rcu(&ifp->if_list). addrconf_dad_failure() then overwrites DEAD with ERRDAD at errdad: and schedules a new dad_work. The work calls ipv6_del_addr() again, hitting the already-poisoned list entry: general protection fault: 0000 [#1] SMP NOPTI CPU: 4 PID: 217 Comm: kworker/4:1 Workqueue: ipv6_addrconf addrconf_dad_work RIP: 0010:ipv6_del_addr+0xe9/0x280 RAX: dead000000000122 Call Trace: addrconf_dad_stop+0x113/0x140 addrconf_dad_work+0x28c/0x430 process_one_work+0x1eb/0x3b0 worker_thread+0x4d/0x400 kthread+0x104/0x140 ret_from_fork+0x35/0x40 Fold the addrconf_dad_end() logic into addrconf_dad_failure() under a single ifp->lock critical section. The STABLE_PRIVACY branch temporarily drops ifp->lock around address regeneration, so at lock_errdad: verify the state is still POSTDAD before transitioning to ERRDAD; bail out otherwise to avoid overwriting a state set by another path while the lock was released.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-08-15

Last Modified

2026-08-17

Generated

2026-09-04

AI Q&A

2026-08-15

EPSS Evaluated

2026-09-03

NVD

CVE-2026-74398

EUVD

EUVD-2026-59545

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This is a Linux kernel vulnerability where a race condition in IPv6 address configuration can cause a kernel panic. The issue occurs when two processes try to modify the same network interface address simultaneously. One process fails during duplicate address detection, while another deletes the address, leading to a corrupted state and a system crash.

Detection Guidance

This vulnerability is specific to the Linux kernel's IPv6 address configuration handling. Detection primarily involves checking kernel logs for general protection faults related to ipv6_del_addr or addrconf_dad_work. Monitor system logs with commands like dmesg | grep -i 'general protection fault' or journalctl -k | grep -i 'ipv6_del_addr'.

Impact Analysis

This vulnerability can cause your Linux system to crash unexpectedly, leading to service disruption. It specifically affects IPv6 network configurations, potentially causing network connectivity issues or system instability when handling address conflicts.

Compliance Impact

This vulnerability is specific to the Linux kernel's IPv6 address configuration and does not directly impact compliance with standards like GDPR or HIPAA. It involves a race condition in address state management that could lead to system crashes but does not involve data exposure or privacy violations.

Mitigation Strategies

Apply the latest kernel security updates from your Linux distribution. If immediate patching is not possible, consider disabling IPv6 temporarily as a workaround, though this may impact network functionality. Monitor vendor advisories for kernel updates addressing this issue.

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