N/A - CVE-2025-21926

Executive Summary

Informations
Name	CVE-2025-21926	First vendor Publication	2025-04-01
Vendor	Cve	Last vendor Modification	2025-04-01

Security-Database Scoring CVSS v3

Cvss vector : N/A
Overall CVSS Score	NA
Base Score	NA	Environmental Score	NA
impact SubScore	NA	Temporal Score	NA
Exploitabality Sub Score	NA

Calculate full CVSS 3.0 Vectors scores

Security-Database Scoring CVSS v2

Cvss vector :
Cvss Base Score	N/A	Attack Range	N/A
Cvss Impact Score	N/A	Attack Complexity	N/A
Cvss Expoit Score	N/A	Authentication	N/A
Calculate full CVSS 2.0 Vectors scores

Detail

In the Linux kernel, the following vulnerability has been resolved:

net: gso: fix ownership in __udp_gso_segment

In __udp_gso_segment the skb destructor is removed before segmenting the skb but the socket reference is kept as-is. This is an issue if the original 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+0x925/0xe50

The above can happen following a sequence of events when using OpenVSwitch, when an OVS_ACTION_ATTR_USERSPACE action precedes an OVS_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.