{"id":"CVE-2025-38732","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_reject: don't leak dst refcount for loopback packets\n\nrecent patches to add a WARN() when replacing skb dst entry found an\nold bug:\n\nWARNING: include/linu…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_reject: don't leak dst refcount for loopback packets\n\nrecent patches to add a WARN() when replacing skb dst entry found an\nold bug:\n\nWARNING: include/linu…","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 >= 5.9, < 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, < 6.12.44","linux_kernel >= 6.13, < 6.16.4","linux_kernel = 6.17","debian_linux = 11.0"],"patched":["linux_kernel 6.16.4"],"published":"2025-09-05","updated":"2026-10-15","sourceUpdated":"2026-10-15T02:17:58.070","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2025-38732","references":[{"url":"https://git.kernel.org/stable/c/51e8531371f90bee742c63775c9a568e5d6bf3c5","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/7b8b503c06274ef3c6c1a107743f1ec0d0a53ef8","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/82ef97abf22790182f7d433c74960dfd61b99c33","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/91a79b792204313153e1bdbbe5acbfc28903b3a5","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a0a3ace2a57887dac1e7c9a724846040c3e31868","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b32e1590a8d22cf7d7f965e46d5576051acf8e42","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b7a885ba25960c91db237c3f83b4285156789bce","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-457936.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"tags":["nvd","cve.org"],"epss":0.00176,"epssPercentile":0.07041,"ingestedAt":"2026-09-08T15:33:26.997Z","slug":"CVE-2025-38732","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_reject: don't leak dst refcount for loopback packets\n\nrecent patches to add a WARN() when replacing skb dst entry found an\nold bug:\n\nWARNING: include/linux/skbuff.h:1165 skb_dst_check_unset include/linux/skbuff.h:1164 [inline]\nWARNING: include/linux/skbuff.h:1165 skb_dst_set include/linux/skbuff.h:1210 [inline]\nWARNING: include/linux/skbuff.h:1165 nf_reject_fill_skb_dst+0x2a4/0x330 net/ipv4/netfilter/nf_reject_ipv4.c:234\n[..]\nCall Trace:\n nf_send_unreach+0x17b/0x6e0 net/ipv4/netfilter/nf_reject_ipv4.c:325\n nft_reject_inet_eval+0x4bc/0x690 net/netfilter/nft_reject_inet.c:27\n expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline]\n ..\n\nThis is because blamed commit forgot about loopback packets.\nSuch packets already have a dst_entry attached, even at PRE_ROUTING stage.\n\nInstead of checking hook just check if the skb already has a route\nattached to it.\n\n## Affected\n\n- `linux_kernel >= 5.9, < 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, < 6.12.44`\n- `linux_kernel >= 6.13, < 6.16.4`\n- `linux_kernel = 6.17`\n- `debian_linux = 11.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 6.16.4`","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":221535,"id":"CVE-2025-38732","ts":1792035255636,"field":"cvss","old":null,"new":"5.5"},{"seq":221534,"id":"CVE-2025-38732","ts":1792035255636,"field":"severity","old":"none","new":"medium"}]}