Vulnerability in Linux Kernel Affects Netfilter Component

CVE-2026-31427

What is CVE-2026-31427?

A vulnerability in the Linux kernel's Netfilter component could allow for the use of uninitialized memory related to SIP session handling. The issue arises within the process_sdp() function, where an uninitialized union variable, rtp_addr, is passed to the nf_nat_sip sdp_session hook. This occurs when the SDP body either lacks valid media lines or contains only inactive or unrecognized media types. As a consequence, the function might invoke the hook with a volatile stack value, which can lead to misconfiguration of session-level addresses in the SDP. To patch this, developers have implemented a fix that pre-initializes rtp_addr when possible and ensures that valid addresses are established before invoking the sdp_session hook.

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