CVE-2026-90104

A flaw was found in the Linux kernel's NFSv4.1 implementation. When decoding callback sequence arguments, an uninitialized pointer in the referring_call_list can be passed to the kfree() function. This memory corruption vulnerability could allow a remote attacker to cause a denial of service by triggering the flaw during NFSv4.1 operations.

An uninitialized pointer bug in the NFSv4.1 callback sequence decoder can occur because decode_cb_sequence_args allocates csa_rclists without zeroing it and decode_rc_list leaves rcl_refcalls unset for a valid empty referring call list. A malicious or compromised NFSv4.1 server can cause the client to later pass stale slab contents to kfree during callback processing, which can crash the kernel and may be treated as a kernel memory corruption candidate. For the CVSS the PR:N is used because the attacker does not need privileges on the victim beyond network reachability as an NFS server endpoint already used by the client. The issue is network reachable through NFS callback processing, but practical exposure is usually limited to trusted storage or data center networks rather than the public Internet. Impact is at least denial of service via kernel crash.

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.