CVE-2026-74430

A flaw was found in the Linux kernel's rxrpc component. A remote attacker could send a specially crafted ACKALL packet that bypasses state validation. This improper handling of forged packets can lead to a null-pointer dereference, causing a Denial of Service (DoS) by crashing the system.

An RXRPC ACKALL handling flaw allows an out of state ACKALL packet to be accepted for a new service call before any reply data has been queued. In RXRPC_CALL_SERVER_RECV_REQUEST, call tx_top can be zero and call tx_queue can be NULL, so processing ACKALL can reach rxrpc_rotate_tx_window and trigger a NULL pointer dereference. For the CVSS the PR:N because a remote peer only needs network reachability to an RXRPC endpoint and does not need local access or authenticated kernel privileges. The issue is network reachable over RXRPC protocol traffic, but practical exposure depends on whether RXRPC or AFS style services are enabled and reachable from untrusted networks. Impact is denial of service via kernel crash. No confidentiality or integrity impact is assigned because the supported primitive is a NULL pointer dereference rather than UAF, OOB access, or arbitrary write.

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.