180 lines
9.9 KiB
JSON
180 lines
9.9 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-2026-98487",
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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": "2026-09-25T10:25:14.352Z",
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"datePublished": "2026-10-18T15:16:04.746Z",
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"dateUpdated": "2026-10-24T14:09:03.998Z"
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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": "2026-10-24T14:09:03.998Z"
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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\nnet: bridge: mdb: restart port group walk after deletion\n\nbr_mdb_flush_pgs() keeps a pointer-to-pointer cursor while walking\nmp->ports. br_multicast_del_pg() can re-enter the same MDB entry through\nbr_multicast_sg_del_exclude_ports() and unlink other port groups. If the\ncursor points into one of those groups, the next iteration dereferences a\nstale cursor and can leave mp->ports pointing at freed memory.\n\nA following RTM_GETMDB exposes the dangling pointer:\n\n BUG: KASAN: slab-use-after-free in br_mdb_dump\n Read of size 8\n br_mdb_dump\n rtnl_mdb_dump\n rtnl_dumpit\n netlink_dump\n\nReset the cursor to mp->ports after every deletion. The deletion removes at\nleast the selected group, so the restarted walk always makes progress."
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}
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],
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"metrics": [
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{
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"cvssV3_1": {
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"version": "3.1",
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"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
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"baseScore": 7.8,
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"baseSeverity": "HIGH"
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},
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"scenarios": [
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{
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"lang": "en",
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"value": "AV:L - A local sendmsg() on NETLINK_ROUTE carrying RTM_DELMDB with NLM_F_BULK reaches the patched br_mdb_flush_pgs() through rtnl_mdb_del() and ndo_mdb_del_bulk; received bridge packets do not enter this bulk-delete path.\nAC:L - The attacker can add a *,G EXCLUDE membership and permanent static S,G groups so br_multicast_sg_add_exclude_ports() creates skipped kernel-protocol STAR_EXCL nodes; a proto-static bulk flush then deterministically invalidates pp without a race.\nPR:L - rtnetlink_rcv_msg() requires CAP_NET_ADMIN through netlink_net_capable(), but an unprivileged user can obtain that capability in a user-created network namespace and create the bridge, ports, and MDB state there.\nUI:N - The attacker performs the RTM_NEWMDB setup, NLM_F_BULK RTM_DELMDB trigger, and optional RTM_GETMDB traversal through their own netlink socket; no victim action is required.\nS:U - The dangling mp->ports pointer corrupts and exposes bridge objects within the host kernel's existing security authority; it does not cross a guest-host, hypervisor, or IOMMU boundary.\nC:H - The persistent slab UAF lets reclaimed contents control p->next and p->key.port; br_mdb_fill_info() follows these links and returns port, timer, flag, and source-list data through RTM_GETMDB, enabling kernel-memory disclosure.\nI:H - Reusing the dangling node in br_multicast_del_pg() reaches hlist_del_init_rcu() through reclaimed pg->mglist.pprev and updates rhashtable and GC links, providing attacker-influenced kernel writes and potential control-flow hijacking.\nA:H - After br_multicast_destroy_port_group() calls kfree_rcu(), br_mdb_dump() produces the confirmed slab-use-after-free; stale p->key.port or p->next dereferences in dump or br_multicast_flood can oops or panic the kernel."
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}
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]
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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/bridge/br_mdb.c"
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],
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"versions": [
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{
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"version": "a6acb535afb2a3b688a7858f05b61f0433e480d5",
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"lessThan": "46ec55855c972504258c371677ac039ba20e5d12",
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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": "a6acb535afb2a3b688a7858f05b61f0433e480d5",
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"lessThan": "ab3c4a4c85f2e1e8d04b5c1770dea8412d21c7fe",
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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": "a6acb535afb2a3b688a7858f05b61f0433e480d5",
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"lessThan": "fe2a42789c12eb7c5d3a42191e2cc735a6c35ead",
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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": "a6acb535afb2a3b688a7858f05b61f0433e480d5",
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"lessThan": "ab1404ac81154a89fb61ac50ae9a04cd8d4834dc",
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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/bridge/br_mdb.c"
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],
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"versions": [
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{
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"version": "6.8",
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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": "6.8",
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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": "6.12.112",
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"lessThanOrEqual": "6.12.*",
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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": "6.18.55",
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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": "7.2.9",
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"lessThanOrEqual": "7.2.*",
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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": "7.3",
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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": "6.8",
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"versionEndExcluding": "6.12.112"
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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": "6.8",
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"versionEndExcluding": "6.18.55"
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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": "6.8",
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"versionEndExcluding": "7.2.9"
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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": "6.8",
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"versionEndExcluding": "7.3"
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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/46ec55855c972504258c371677ac039ba20e5d12"
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},
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{
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"url": "https://git.kernel.org/stable/c/ab3c4a4c85f2e1e8d04b5c1770dea8412d21c7fe"
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},
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{
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"url": "https://git.kernel.org/stable/c/fe2a42789c12eb7c5d3a42191e2cc735a6c35ead"
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},
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{
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"url": "https://git.kernel.org/stable/c/ab1404ac81154a89fb61ac50ae9a04cd8d4834dc"
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}
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],
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"title": "net: bridge: mdb: restart port group walk after deletion",
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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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} |