{"id":"CVE-2025-39963","title":"kernel: io_uring: fix incorrect io_kiocb reference in io_link_skb (CVE-2025-39963)","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring: fix incorrect io_kiocb reference in io_link_skb\n\nIn io_link_skb function, there is a bug where prev_notif is incorrectly\nassigned using 'nd' instead of 'prev_nd…","severity":"medium","cvss":5.5,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","cvssSource":"vendor","cwe":"CWE-1025","vendor":"Red Hat","product":"Red Hat Enterprise Linux 9","affected":["enterprise_linux 10","enterprise_linux 9"],"published":"2025-10-09","updated":"2026-10-16","sourceUpdated":"2026-10-16T23:24:05+00:00","source":"CSAF","sourceUrl":"https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-39963.json","references":[{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-39963.json"},{"url":"https://access.redhat.com/security/cve/CVE-2025-39963"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2402718"},{"url":"https://www.cve.org/CVERecord?id=CVE-2025-39963"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2025-39963"},{"url":"https://lore.kernel.org/linux-cve-announce/2025100917-CVE-2025-39963-b0ff@gregkh/T"},{"url":"https://git.kernel.org/stable/c/a89c34babc2e5834aa0905278f26f4dbe4b26b76"},{"url":"https://git.kernel.org/stable/c/50a98ce1ea694f1ff8e87bc2f8f84096d1736f6a"},{"url":"https://git.kernel.org/stable/c/2c139a47eff8de24e3350dadb4c9d5e3426db826"}],"tags":["csaf","vex","red-hat","cve.org","score-dispute"],"epss":0.00152,"epssPercentile":0.0432,"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-15T21:55:14.622512Z"},"scores":{"vendor":5.5,"cna":7.8},"ingestedAt":"2026-10-15T22:48:25.532Z","slug":"CVE-2025-39963","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nio_uring: fix incorrect io_kiocb reference in io_link_skb\n\nIn io_link_skb function, there is a bug where prev_notif is incorrectly\nassigned using 'nd' instead of 'prev_nd'. This causes the context\nvalidation check to compare the current notification with itself instead\nof comparing it with the previous notification.\n\nFix by using the correct prev_nd parameter when obtaining prev_notif.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Low · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9 · updated 2026-10-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-39963.json)\n\n**kernel: io_uring: fix incorrect io_kiocb reference in io_link_skb** — rated Low by Red Hat. Released 2025-10-09, updated 2026-10-16.\n\nAffected:\n\n- Red Hat Enterprise Linux 10\n- Red Hat Enterprise Linux 9\n\nNo fix planned:\n\n- Red Hat Enterprise Linux 10\n- Red Hat Enterprise Linux 9\n\nNot affected:\n\n- Red Hat Enterprise Linux 6\n- Red Hat Enterprise Linux 7\n- Red Hat Enterprise Linux 8\n\n## Remediation\n\nFix deferred\n\nWorkarounds / mitigations:\n\n- Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":223564,"id":"CVE-2025-39963","ts":1792238317191,"field":"cvss","old":"7.8","new":"5.5"},{"seq":223563,"id":"CVE-2025-39963","ts":1792238317191,"field":"severity","old":"high","new":"medium"}]}