{"cve":"CVE-2026-31427","nvd":{"published":"2026-04-13T14:16:12.783","modified":"2026-10-15T02:19:04.573","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_conntrack_sip: fix use of uninitialized rtp_addr in process_sdp\n\nprocess_sdp() declares union nf_inet_addr rtp_addr on the stack and\npasses it to the nf_nat_sip sdp_session hook after walking the SDP\nmedia descriptions. However rtp_addr is only initialized inside the\nmedia loop when a recognized media type with a non-zero port is found.\n\nIf the SDP body contains no m= lines, only inactive media sections\n(m=audio 0 ...) or only unrecognized media types, rtp_addr is never\nassigned. Despite that, the function still calls hooks->sdp_session()\nwith &rtp_addr, causing nf_nat_sdp_session() to format the stale stack\nvalue as an IP address and rewrite the SDP session owner and connection\nlines with it.\n\nWith CONFIG_INIT_STACK_ALL_ZERO (default on most distributions) this\nresults in the session-level o= and c= addresses being rewritten to\n0.0.0.0 for inactive SDP sessions. Without stack auto-init the\nrewritten address is whatever happened to be on the stack.\n\nFix this by pre-initializing rtp_addr from the session-level connection\naddress (caddr) when available, and tracking via a have_rtp_addr flag\nwhether any valid address was established. Skip the sdp_session hook\nentirely when no valid address exists.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":["CWE-908"],"references":["https://git.kernel.org/stable/c/01f34a80ac23ae90b1909b94b4ed05343a62f646","https://git.kernel.org/stable/c/52fdda318ef2362fc5936385bcb8b3d0328ee629","https://git.kernel.org/stable/c/6a2b724460cb67caed500c508c2ae5cf012e4db4","https://git.kernel.org/stable/c/6e5e3c87b7e6212f1d8414fc2e4d158b01e12025","https://git.kernel.org/stable/c/7edca70751b9bdb5b83eed53cde21eccf3c86147"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:30:49.762551342+00:00"},"epss":{"cve":"CVE-2026-31427","score":0.0012,"percentile":0.01836,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}