{"id":"CVE-2025-39764","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: ctnetlink: remove refcounting in expectation dumpers\n\nSame pattern as previous patch: do not keep the expectation object\nalive via refcount, only store a coo…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: ctnetlink: remove refcounting in expectation dumpers\n\nSame pattern as previous patch: do not keep the expectation object\nalive via refcount, only store a coo…","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","vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 2.6.23, < 6.16.2","linux_kernel = 6.17"],"patched":["linux_kernel 6.16.2"],"published":"2025-09-11","updated":"2026-10-15","sourceUpdated":"2026-10-15T02:18:00.120","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2025-39764","references":[{"url":"https://git.kernel.org/stable/c/078d33c95bf534d37aa04269d1ae6158e20082d5","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/1492e3dcb2be3aa46d1963da96aa9593e4e4db5a","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/64b7684042246e3238464c66894e30ba30c7e851","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/9e5021a906532ca16e2aac69c0607711e1c70b1f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a4d634ded4d3d400f115d84f654f316f249531c9","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b05500444b8eb97644efdd180839a04a706be97c","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/bada48ad5b0590e318d0f79636ff62a2ef9f4955","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-019113.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-082556.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-457936.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"tags":["nvd","cve.org"],"epss":0.00173,"epssPercentile":0.06759,"ingestedAt":"2026-09-08T15:33:26.997Z","slug":"CVE-2025-39764","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: ctnetlink: remove refcounting in expectation dumpers\n\nSame pattern as previous patch: do not keep the expectation object\nalive via refcount, only store a cookie value and then use that\nas the skip hint for dump resumption.\n\nAFAICS this has the same issue as the one resolved in the conntrack\ndumper, when we do\n  if (!refcount_inc_not_zero(&exp->use))\n\nto increment the refcount, there is a chance that exp == last, which\ncauses a double-increment of the refcount and subsequent memory leak.\n\n## Affected\n\n- `linux_kernel >= 2.6.23, < 6.16.2`\n- `linux_kernel = 6.17`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 6.16.2`","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":221547,"id":"CVE-2025-39764","ts":1792035257906,"field":"cvss","old":null,"new":"5.5"},{"seq":221546,"id":"CVE-2025-39764","ts":1792035257906,"field":"severity","old":"none","new":"medium"}]}