CVE-2025-39828

A flaw was found in the Linux kernel’s ATM (Asynchronous Transfer Mode) TCP subsystem function atmtcp_recv_control(). Because the message length from user space is not validated in sendmsg(), a malicious local user may craft a special ATMTCP control message that overwrites an in-kernel pointer (via atmtcp_control.vcc), causing an arbitrary write leading damage to confidentiality,integrity and availability.

This vulnerability is rated as Moderate impact for Red Hat Enterprise Linux because exploitation requires local access on hosts with the legacy ATM over TCP driver enabled. The atmtcp driver is not loaded by default in standard enterprise deployments, significantly limiting the attack surface. Although a local attacker could trigger kernel memory corruption and potentially achieve arbitrary writes, ATM networking protocols are rarely deployed in modern production environments.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.