CVE-2026-74401

Summary

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

dlm: fix add msg handle in send_queue ordered

In a benchmark scenario triggering a lot of requests that triggers a lot of DLM messages on the network it can be that the mh->seq is not ordered according the oldest seq number. This ordering is required by dlm_receive_ack as "before(mh->seq, seq)" will stop to check for older sequence numbers that are ordered in the tail of "node->send_queue".

The side effects of not having it correct ordered regarding "before(mh->seq, seq)" are refcounting issues and use-after free.

I only was able to reproduce this issue in a experimental DLM branch and a user space DLM benchmark that uses io_uring. After changing this I don't experienced any refcounting with the sending buffer issues anymore.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux489d8e559c6596eb08e16447d9830bc39afbe54e < ae9e534e502a0f48c12baf83608c5de0ff0eab11affected
LinuxLinux489d8e559c6596eb08e16447d9830bc39afbe54e < 6369619f1b665f12d8c99cc6ff733c64eb08b22eaffected
LinuxLinux489d8e559c6596eb08e16447d9830bc39afbe54e < 712714f818d83373847874ab0f8e426be79296cfaffected
LinuxLinux489d8e559c6596eb08e16447d9830bc39afbe54e < 4d45250b1d22960f86d83245be188b16e456218baffected
LinuxLinux489d8e559c6596eb08e16447d9830bc39afbe54e < d2248cb70c070f8f04762872772e155b59016f17affected
LinuxLinux5.14affected
LinuxLinux0 < 5.14unaffected
LinuxLinux6.6.145 <= 6.6.*unaffected
LinuxLinux6.12.97 <= 6.12.*unaffected
LinuxLinux6.18.40 <= 6.18.*unaffected
LinuxLinux7.1.5 <= 7.1.*unaffected
LinuxLinux7.2-rc1 <= *unaffected

Weaknesses

References