CVE-2026-89479

A flaw was found in the Linux kernel's Stream Control Transmission Protocol (SCTP) implementation. A remote attacker could send a specially crafted series of SCTP packets, leading to a use-after-free vulnerability. This occurs when the kernel attempts to access memory that has already been deallocated, which could result in a denial of service.

Important impact is assigned to this flaw because an attacker transmitting malformed chunk sequences within an SCTP packet can trigger a use-after-free condition in kernel space, potentially leading to system instability or memory corruption. On default Red Hat Enterprise Linux installations, the SCTP kernel module is not loaded unless explicitly initiated by an administrator or configured service. Exposure is primarily limited to environments running network services that bind SCTP endpoints or systems where untrusted local users can create SCTP sockets in unprivileged user namespaces.

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.

To mitigate this vulnerability, prevent the SCTP kernel module from loading on systems where the protocol is not needed:

1. Disable loading of the sctp module:

# echo "install sctp /bin/true" > /etc/modprobe.d/disable-sctp.conf

2. If the module is currently loaded, unload it or reboot the system:

# modprobe -r sctp

Warning: If the module is in use, unloading it will fail, and a full system restart is required to eliminate the loaded module from kernel memory.

Caveat: Disabling the SCTP module will prevent services or applications that require SCTP network communications from operating.