122 lines
7.0 KiB
JSON
122 lines
7.0 KiB
JSON
{
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"dataType": "CVE_RECORD",
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"dataVersion": "5.2",
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"cveMetadata": {
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"cveId": "CVE-2026-23016",
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"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"state": "PUBLISHED",
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"assignerShortName": "Linux",
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"dateReserved": "2026-01-13T15:37:45.940Z",
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"datePublished": "2026-01-31T11:38:59.578Z",
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"dateUpdated": "2026-05-11T21:58:22.462Z"
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},
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"containers": {
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"cna": {
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"providerMetadata": {
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"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"shortName": "Linux",
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"dateUpdated": "2026-05-11T21:58:22.462Z"
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},
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"descriptions": [
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{
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"lang": "en",
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ninet: frags: drop fraglist conntrack references\n\nJakub added a warning in nf_conntrack_cleanup_net_list() to make debugging\nleaked skbs/conntrack references more obvious.\n\nsyzbot reports this as triggering, and I can also reproduce this via\nip_defrag.sh selftest:\n\n conntrack cleanup blocked for 60s\n WARNING: net/netfilter/nf_conntrack_core.c:2512\n [..]\n\nconntrack clenups gets stuck because there are skbs with still hold nf_conn\nreferences via their frag_list.\n\n net.core.skb_defer_max=0 makes the hang disappear.\n\nEric Dumazet points out that skb_release_head_state() doesn't follow the\nfraglist.\n\nip_defrag.sh can only reproduce this problem since\ncommit 6471658dc66c (\"udp: use skb_attempt_defer_free()\"), but AFAICS this\nproblem could happen with TCP as well if pmtu discovery is off.\n\nThe relevant problem path for udp is:\n1. netns emits fragmented packets\n2. nf_defrag_v6_hook reassembles them (in output hook)\n3. reassembled skb is tracked (skb owns nf_conn reference)\n4. ip6_output refragments\n5. refragmented packets also own nf_conn reference (ip6_fragment\n calls ip6_copy_metadata())\n6. on input path, nf_defrag_v6_hook skips defragmentation: the\n fragments already have skb->nf_conn attached\n7. skbs are reassembled via ipv6_frag_rcv()\n8. skb_consume_udp -> skb_attempt_defer_free() -> skb ends up\n in pcpu freelist, but still has nf_conn reference.\n\nPossible solutions:\n 1 let defrag engine drop nf_conn entry, OR\n 2 export kick_defer_list_purge() and call it from the conntrack\n netns exit callback, OR\n 3 add skb_has_frag_list() check to skb_attempt_defer_free()\n\n2 & 3 also solve ip_defrag.sh hang but share same drawback:\n\nSuch reassembled skbs, queued to socket, can prevent conntrack module\nremoval until userspace has consumed the packet. While both tcp and udp\nstack do call nf_reset_ct() before placing skb on socket queue, that\nfunction doesn't iterate frag_list skbs.\n\nTherefore drop nf_conn entries when they are placed in defrag queue.\nKeep the nf_conn entry of the first (offset 0) skb so that reassembled\nskb retains nf_conn entry for sake of TX path.\n\nNote that fixes tag is incorrect; it points to the commit introducing the\n'ip_defrag.sh reproducible problem': no need to backport this patch to\nevery stable kernel."
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}
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],
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"affected": [
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{
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"product": "Linux",
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"vendor": "Linux",
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"defaultStatus": "unaffected",
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"programFiles": [
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"net/ipv4/inet_fragment.c"
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],
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"versions": [
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{
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"version": "6471658dc66c670580a7616e75f51b52917e7883",
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"lessThan": "088ca99dbb039c444c3ff987c5412a73f4f0cbf8",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "6471658dc66c670580a7616e75f51b52917e7883",
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"lessThan": "2ef02ac38d3c17f34a00c4b267d961a8d4b45d1a",
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"status": "affected",
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"versionType": "git"
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}
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]
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},
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{
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"product": "Linux",
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"vendor": "Linux",
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"defaultStatus": "affected",
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"programFiles": [
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"net/ipv4/inet_fragment.c"
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],
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"versions": [
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{
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"version": "6.18",
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"status": "affected"
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},
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{
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"version": "0",
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"lessThan": "6.18",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.18.6",
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"lessThanOrEqual": "6.18.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.19",
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"lessThanOrEqual": "*",
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"status": "unaffected",
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"versionType": "original_commit_for_fix"
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}
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]
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}
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],
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"cpeApplicability": [
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{
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"nodes": [
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{
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"operator": "OR",
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"negate": false,
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"cpeMatch": [
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "6.18",
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"versionEndExcluding": "6.18.6"
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},
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "6.18",
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"versionEndExcluding": "6.19"
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}
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]
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}
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]
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}
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],
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"references": [
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{
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"url": "https://git.kernel.org/stable/c/088ca99dbb039c444c3ff987c5412a73f4f0cbf8"
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},
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{
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"url": "https://git.kernel.org/stable/c/2ef02ac38d3c17f34a00c4b267d961a8d4b45d1a"
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}
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],
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"title": "inet: frags: drop fraglist conntrack references",
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"x_generator": {
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"engine": "bippy-1.2.0"
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}
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}
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}
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} |