{"id":"CVE-2025-38721","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: ctnetlink: fix refcount leak on table dump\n\nThere is a reference count leak in ctnetlink_dump_table():\n      if (res < 0) {\n                nf_conntrack_get(…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: ctnetlink: fix refcount leak on table dump\n\nThere is a reference count leak in ctnetlink_dump_table():\n      if (res < 0) {\n                nf_conntrack_get(…","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 >= 2.6.19, < 5.4.297","linux_kernel >= 5.5, < 5.10.241","linux_kernel >= 5.11, < 5.15.190","linux_kernel >= 5.16, < 6.1.149","linux_kernel >= 6.2, < 6.6.103","linux_kernel >= 6.7, < 6.12.43","linux_kernel >= 6.13, < 6.15.11","linux_kernel >= 6.16, < 6.16.2","linux_kernel = 2.6.18","linux_kernel = 6.17","debian_linux = 11.0"],"patched":["linux_kernel 6.16.2"],"published":"2025-09-04","updated":"2026-10-15","sourceUpdated":"2026-10-15T02:17:57.323","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2025-38721","references":[{"url":"https://git.kernel.org/stable/c/19b909a4b1452fb97e477d2f08b97f8d04095619","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/30cf811058552b8cd0e98dff677ef3f89d6d34ce","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/41462f4cfc583513833f87f9ee55d12da651a7e3","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/586892e341fbf698e7cbaca293e1353957db725a","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/962518c6ca9f9a13df099cafa429f72f68ad61f0","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a2cb4df7872de069f809de2f076ec8e54d649fe3","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a62d6aa3f31f216b637a4c71b7a8bfc7c57f049b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/de788b2e6227462b6dcd0e07474e72c089008f74","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e14f72aa66c029db106921d621edcedef68e065b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"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-032379.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":0.0017,"epssPercentile":0.06356,"ingestedAt":"2026-09-08T15:33:26.997Z","slug":"CVE-2025-38721","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: ctnetlink: fix refcount leak on table dump\n\nThere is a reference count leak in ctnetlink_dump_table():\n      if (res < 0) {\n                nf_conntrack_get(&ct->ct_general); // HERE\n                cb->args[1] = (unsigned long)ct;\n                ...\n\nWhile its very unlikely, its possible that ct == last.\nIf this happens, then the refcount of ct was already incremented.\nThis 2nd increment is never undone.\n\nThis prevents the conntrack object from being released, which in turn\nkeeps prevents cnet->count from dropping back to 0.\n\nThis will then block the netns dismantle (or conntrack rmmod) as\nnf_conntrack_cleanup_net_list() will wait forever.\n\nThis can be reproduced by running conntrack_resize.sh selftest in a loop.\nIt takes ~20 minutes for me on a preemptible kernel on average before\nI see a runaway kworker spinning in nf_conntrack_cleanup_net_list.\n\nOne fix would to change this to:\n        if (res < 0) {\n\t\tif (ct != last)\n\t                nf_conntrack_get(&ct->ct_general);\n\nBut this reference counting isn't needed in the first place.\nWe can just store a cookie value instead.\n\nA followup patch will do the same for ctnetlink_exp_dump_table,\nit looks to me as if this has the same problem and like\nctnetlink_dump_table, we only need a 'skip hint', not the actual\nobject so we can apply the same cookie strategy there as well.\n\n## Affected\n\n- `linux_kernel >= 2.6.19, < 5.4.297`\n- `linux_kernel >= 5.5, < 5.10.241`\n- `linux_kernel >= 5.11, < 5.15.190`\n- `linux_kernel >= 5.16, < 6.1.149`\n- `linux_kernel >= 6.2, < 6.6.103`\n- `linux_kernel >= 6.7, < 6.12.43`\n- `linux_kernel >= 6.13, < 6.15.11`\n- `linux_kernel >= 6.16, < 6.16.2`\n- `linux_kernel = 2.6.18`\n- `linux_kernel = 6.17`\n- `debian_linux = 11.0`\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":221529,"id":"CVE-2025-38721","ts":1792035254662,"field":"cvss","old":null,"new":"5.5"},{"seq":221528,"id":"CVE-2025-38721","ts":1792035254662,"field":"severity","old":"none","new":"medium"}]}