Bug 2348601 (CVE-2025-21791)

Summary: CVE-2025-21791 kernel: vrf: use RCU protection in l3mdev_l3_out()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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A use-after-free vulnerability was found in the Linux kernel. l3mdev_l3_out() can be called without RCU being held, causing damage to the availability of the system.
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Description OSIDB Bzimport 2025-02-27 03:04:43 UTC
In the Linux kernel, the following vulnerability has been resolved:

vrf: use RCU protection in l3mdev_l3_out()

l3mdev_l3_out() can be called without RCU being held:

raw_sendmsg()
 ip_push_pending_frames()
  ip_send_skb()
   ip_local_out()
    __ip_local_out()
     l3mdev_ip_out()

Add rcu_read_lock() / rcu_read_unlock() pair to avoid
a potential UAF.