CVE intelligence

CVE-2025-38544

Vulnerability intelligence

Published Aug 16, 2025Sources checked Oct 21, 2026

5.5MEDIUMCVSS out of 10

What this means

Review the available evidence

CVE-2025-38544 and is rated Medium severity with a CVSS score of 5.5. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: Oct 17, 2026

CBL-Mariner Releases Release Notes

Vendor-listed releases

6.6.104.2-1

CISA KEVNot listedBased on the latest collected catalog

EPSS0.2%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2025-38544?

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

rxrpc: Fix bug due to prealloc collision

When userspace is using AF_RXRPC to provide a server, it has to preallocate incoming calls and assign to them call IDs that will be used to thread related recvmsg() and sendmsg() together. The preallocated call IDs will automatically be attached to calls as they come in until the pool is empty.

To the kernel, the call IDs are just arbitrary numbers, but userspace can use the call ID to hold a pointer to prepared structs. In any case, the user isn't permitted to create two calls with the same call ID (call IDs become available again when the call ends) and EBADSLT should result from sendmsg() if an attempt is made to preallocate a call with an in-use call ID.

However, the cleanup in the error handling will trigger both assertions in rxrpc_cleanup_call() because the call isn't marked complete and isn't marked as having been released.

Fix this by setting the call state in rxrpc_service_prealloc_one() and then marking it as being released before calling the cleanup function.

Source: NVD