CVE-2026-97954

A flaw was found in the Linux kernel's Reliable Datagram Sockets (RDS) subsystem. This vulnerability allows a network user to cause a Denial of Service (DoS) by corrupting TCP communication streams. On systems configured with memory page sizes larger than 8 KB, the kernel incorrectly calculates buffer lengths when mapping memory pages for RDS congestion maps. Consequently, extraneous bytes are transmitted across the network connection and misread as message headers, corrupting the stream and causing connections to hang.

A moderate impact flaw was found in the Linux kernel's Reliable Datagram Sockets (RDS) subsystem. In rds_message_map_pages(), a full PAGE_SIZE length is assigned to every scatterlist entry even when the mapped total length ends in a partial page. Because the RDS congestion map is defined as 8192 bytes, on systems configured with a memory page size larger than 8 KB (for example 16 KB or 64 KB pages), the scatterlist maps bytes beyond the end of the congestion map. RDS-TCP transmits those extra bytes according to the scatterlist lengths, and the receiving peer interprets them as subsequent RDS message headers, corrupting the TCP stream and causing RDS-TCP connections to hang, which results in a denial of service against the RDS transport. Systems using a 4 KB page size are not affected, and triggering the flaw requires RDS-TCP on a system built with a larger page size, an uncommon configuration; for this reason Red Hat assesses the impact of this flaw as moderate. All currently listed Red Hat products, including Red Hat Enterprise Linux, Red Hat Enterprise Linux for Real Time, Red Hat In-Vehicle OS, and OpenShift Container Platform RHCOS components, are not affected because the vulnerable code is not present; Red Hat Enterprise Linux 6 Extended Lifecycle Support is out of support scope.

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 do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.