cve/2025/CVE-2025-21926.md

### [CVE-2025-21926](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2025-21926)
![](https://img.shields.io/static/v1?label=Product&message=Linux&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=&color=brightgreen)
![](https://img.shields.io/static/v1?label=Version&message=4.18%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Version&message=ad405857b174ed31a97982bb129c320d03321cf5%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=n%2Fa&color=blue)

### Description

In the Linux kernel, the following vulnerability has been resolved:net: gso: fix ownership in __udp_gso_segmentIn __udp_gso_segment the skb destructor is removed before segmenting theskb but the socket reference is kept as-is. This is an issue if theoriginal skb is later orphaned as we can hit the following bug:  kernel BUG at ./include/linux/skbuff.h:3312!  (skb_orphan)  RIP: 0010:ip_rcv_core+0x8b2/0xca0  Call Trace:   ip_rcv+0xab/0x6e0   __netif_receive_skb_one_core+0x168/0x1b0   process_backlog+0x384/0x1100   __napi_poll.constprop.0+0xa1/0x370   net_rx_action+0x925/0xe50The above can happen following a sequence of events when usingOpenVSwitch, when an OVS_ACTION_ATTR_USERSPACE action precedes anOVS_ACTION_ATTR_OUTPUT action:1. OVS_ACTION_ATTR_USERSPACE is handled (in do_execute_actions): the skb   goes through queue_gso_packets and then __udp_gso_segment, where its   destructor is removed.2. The segments' data are copied and sent to userspace.3. OVS_ACTION_ATTR_OUTPUT is handled (in do_execute_actions) and the   same original skb is sent to its path.4. If it later hits skb_orphan, we hit the bug.Fix this by also removing the reference to the socket in__udp_gso_segment.

### POC

#### Reference
No PoCs from references.

#### Github
- https://github.com/ARPSyndicate/cve-scores
- https://github.com/runwhen-contrib/helm-charts
- https://github.com/w4zu/Debian_security