CVE-2026-74489 Linux CVE debrief

Who should care

Linux kernel developers and users, mac80211 module users, individuals responsible for maintaining and securing Linux-based systems, and security teams monitoring for potential exploitation attempts of this vulnerability in their environments. They should be aware of the vulnerability's impact and take necessary actions to mitigate it, such as applying patches or workarounds provided by the Linux kernel maintainers. Additionally, users of affected systems should review and test patched kernel versions to ensure the vulnerability is properly addressed. Monitoring for potential exploitation attempts is also crucial to prevent or minimize the impact of an attack. This includes reviewing system logs, using intrusion detection systems, and staying informed about any emerging threats related to this vulnerability. By taking these steps, Linux kernel developers and users can help protect their systems from potential attacks exploiting this vulnerability. The vulnerability's resolution demonstrates the importance of careful synchronization and locking in concurrent programming to prevent use-after-free errors that can lead to security vulnerabilities. Therefore, it is essential for developers to prioritize secure coding practices and thorough testing to identify and address such issues before they can be exploited. Individuals and organizations using Linux-based systems must stay vigilant and proactive in applying security patches and updates to prevent exploitation of known vulnerabilities like this one. This involves regularly reviewing and updating system configurations, monitoring security advisories, and engaging with the Linux community and security experts to stay informed about potential risks and mitigation strategies. Ultimately, a collaborative effort between developers, users, and security professionals is crucial in addressing and mitigating the impact of vulnerabilities like the one described in this CVE record. By working together, we can enhance the security and stability of Linux-based systems and protect them from potential threats. Linux kernel developers and users must prioritize security and take proactive steps to prevent exploitation of this and A

Technical summary

The vulnerability is caused by a use-after-free error in the `ieee80211_stop_tx_ba_cb` function. The function hands `tid_tx` to `kfree_rcu` and then reads `tid_tx->ndp` after dropping `sta->lock`. This can lead to a use-after-free error if the RCU callback frees `tid_tx` before the read. The fix involves reading `ndp` into a local variable before the session is freed, while `sta->lock` is still held.

Defensive priority

High

Recommended defensive actions

• Apply the patch to update the Linux kernel
• Review and test the patched kernel version
• Monitor for potential exploitation attempts
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Check relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The vulnerability was resolved by reading `ndp` into a local variable before the session is freed, while `sta->lock` is still held. The `tid_tx->ndp` has a single writer in `ieee80211_tx_ba_session_handle_start`, which cannot run concurrently here.

Official resources