CyberRota Analysis
AI-GeneratedThe vulnerability affects the Linux kernel's handling of out-of-band (OOB) messages in the rxrpc subsystem, where a peeked message can be incorrectly moved onto a pending queue, leading to memory corruption. This flaw allows for a use-after-free condition due to double freeing of the same socket buffer, which can result in system instability or exploitation. Organizations using affected Linux kernel versions, particularly those relying on rxrpc for communication, should prioritize patching to mitigate potential risks.
Original NVD Description
In the Linux kernel, the following vulnerability has been resolved: rxrpc: Don't move a peeked OOB message onto the pending queue rxrpc_recvmsg_oob() takes a received oob message off recvmsg_oobq and, if a response is needed, moves it onto the pending_oobq tree. However, only the unlink from recvmsg_oobq is guarded by MSG_PEEK; the move onto pending_oobq always runs. As a result, reading a challenge with MSG_PEEK leaves the skb on recvmsg_oobq while also adding it to pending_oobq. Since struct sk_buff's rbnode shares storage with its next and prev pointers, rb_insert_color() overwrites the list linkage, and the skb, which holds a single reference, becomes reachable from both queues at once. When the socket is closed both queues are drained in turn. While draining recvmsg_oobq, __skb_unlink() follows the next and prev pointers that rbnode has overwritten and writes to a bad address. Also, as the skb holds a single reference but is freed from each queue, both the skb and the connection reference it holds are released twice. This leads to memory corruption and to a use-after-free caused by the connection refcount underflow. MSG_PEEK does not consume the message from the queue, so only unlink it from recvmsg_oobq and then move it onto pending_oobq or free it when the message is actually consumed.