CVE-2026-23004 Linux CVE debrief

Who should care

Linux system administrators and users should assess exposure and apply patches or mitigations as needed. This includes verifying Linux kernel versions, inventorying Linux systems, and monitoring for suspicious activity. Security teams should review and apply patches, track exceptions, and retest remediated assets.

Why it matters

A use-after-free vulnerability in the Linux kernel's dst: fix races in rt6_uncached_list_del() and rt_del_uncached_list() may lead to a crash. Linux system administrators and users should assess exposure and apply patches or mitigations as needed.

• Verify Linux kernel versions and apply patches
• Inventory Linux systems for exposure
• Monitor for suspicious activity

Technical summary

The Linux kernel's dst: fix races in rt6_uncached_list_del() and rt_del_uncached_list() has a use-after-free vulnerability. This issue occurs when list_del_init()/INIT_LIST_HEAD() is executed while writing list->prev, due to a prior write on list->next going well. The vulnerability arises from rt6_uncached_list_del() not locking ul->lock when list_empty(&rt->dst.rt_uncached) returns true, potentially causing a crash. This can be fixed by using list_del_init_careful() and list_empty_careful(), or ensuring rt6_uncached_list_del() grabs the spinlock when rt->dst.rt_uncached_list is set.

Defensive priority

Medium

Recommended defensive actions

• Review and apply patches from Linux vendors
• Inventory Linux systems for exposure
• Monitor for suspicious activity
• Verify Linux kernel versions and apply patches
• 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 CVE record and source item provide details about the vulnerability, including its description and affected versions. However, the corpus does not establish versions, exploitation, impact, or remediation, which require verification from the supplied official sources. Further review of Linux kernel documentation and official advisories is necessary to fully understand the vulnerability and its mitigations.

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.