CVE-2025-21926

Summary

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.

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxad405857b174ed31a97982bb129c320d03321cf5 < 9f28205ddb76e86cac418332e952241d85fed0dcaffected
LinuxLinuxad405857b174ed31a97982bb129c320d03321cf5 < a2d1cca955ed34873e524cc2e6e885450d262f05affected
LinuxLinuxad405857b174ed31a97982bb129c320d03321cf5 < 455217ac9db0cf9349b3933664355e907bb1a569affected
LinuxLinuxad405857b174ed31a97982bb129c320d03321cf5 < e8db70537878e1bb3fd83e5abcc6feefc0587828affected
LinuxLinuxad405857b174ed31a97982bb129c320d03321cf5 < 01a83237644d6822bc7df2c5564fc81b0df84358affected
LinuxLinuxad405857b174ed31a97982bb129c320d03321cf5 < 084819b0d8b1bd433b90142371eb9450d657f8caaffected
LinuxLinuxad405857b174ed31a97982bb129c320d03321cf5 < c32da44cc9298eaa6109e3fc2c2b4e07cc4bf11baffected
LinuxLinuxad405857b174ed31a97982bb129c320d03321cf5 < ee01b2f2d7d0010787c2343463965bbc283a497faffected
LinuxLinux4.18affected
LinuxLinux0 < 4.18unaffected
LinuxLinux5.4.291 <= 5.4.*unaffected
LinuxLinux5.10.235 <= 5.10.*unaffected
LinuxLinux5.15.179 <= 5.15.*unaffected
LinuxLinux6.1.131 <= 6.1.*unaffected
LinuxLinux6.6.83 <= 6.6.*unaffected
LinuxLinux6.12.19 <= 6.12.*unaffected
LinuxLinux6.13.7 <= 6.13.*unaffected
LinuxLinux6.14 <= *unaffected

Weaknesses

ADP Enrichment

CVE Program Container

Additional References

References