{
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"cveMetadata": {
"cveId": "CVE-2025-38476",
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"state": "PUBLISHED",
"assignerShortName": "Linux",
"dateReserved": "2025-04-16T04:51:24.021Z",
"datePublished": "2025-07-28T11:21:37.175Z",
"dateUpdated": "2026-08-05T12:02:13.331Z"
},
"containers": {
"cna": {
"providerMetadata": {
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux",
"dateUpdated": "2026-08-05T12:02:13.331Z"
},
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrpl: Fix use-after-free in rpl_do_srh_inline().\n\nRunning lwt_dst_cache_ref_loop.sh in selftest with KASAN triggers\nthe splat below [0].\n\nrpl_do_srh_inline() fetches ipv6_hdr(skb) and accesses it after\nskb_cow_head(), which is illegal as the header could be freed then.\n\nLet's fix it by making oldhdr to a local struct instead of a pointer.\n\n[0]:\n[root@fedora net]# ./lwt_dst_cache_ref_loop.sh\n...\nTEST: rpl (input)\n[ 57.631529] ==================================================================\nBUG: KASAN: slab-use-after-free in rpl_do_srh_inline.isra.0 (net/ipv6/rpl_iptunnel.c:174)\nRead of size 40 at addr ffff888122bf96d8 by task ping6/1543\n\nCPU: 50 UID: 0 PID: 1543 Comm: ping6 Not tainted 6.16.0-rc5-01302-gfadd1e6231b1 #23 PREEMPT(voluntary)\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\nCall Trace:\n \n dump_stack_lvl (lib/dump_stack.c:122)\n print_report (mm/kasan/report.c:409 mm/kasan/report.c:521)\n kasan_report (mm/kasan/report.c:221 mm/kasan/report.c:636)\n kasan_check_range (mm/kasan/generic.c:175 (discriminator 1) mm/kasan/generic.c:189 (discriminator 1))\n __asan_memmove (mm/kasan/shadow.c:94 (discriminator 2))\n rpl_do_srh_inline.isra.0 (net/ipv6/rpl_iptunnel.c:174)\n rpl_input (net/ipv6/rpl_iptunnel.c:201 net/ipv6/rpl_iptunnel.c:282)\n lwtunnel_input (net/core/lwtunnel.c:459)\n ipv6_rcv (./include/net/dst.h:471 (discriminator 1) ./include/net/dst.h:469 (discriminator 1) net/ipv6/ip6_input.c:79 (discriminator 1) ./include/linux/netfilter.h:317 (discriminator 1) ./include/linux/netfilter.h:311 (discriminator 1) net/ipv6/ip6_input.c:311 (discriminator 1))\n __netif_receive_skb_one_core (net/core/dev.c:5967)\n process_backlog (./include/linux/rcupdate.h:869 net/core/dev.c:6440)\n __napi_poll.constprop.0 (net/core/dev.c:7452)\n net_rx_action (net/core/dev.c:7518 net/core/dev.c:7643)\n handle_softirqs (kernel/softirq.c:579)\n do_softirq (kernel/softirq.c:480 (discriminator 20))\n \n \n __local_bh_enable_ip (kernel/softirq.c:407)\n __dev_queue_xmit (net/core/dev.c:4740)\n ip6_finish_output2 (./include/linux/netdevice.h:3358 ./include/net/neighbour.h:526 ./include/net/neighbour.h:540 net/ipv6/ip6_output.c:141)\n ip6_finish_output (net/ipv6/ip6_output.c:215 net/ipv6/ip6_output.c:226)\n ip6_output (./include/linux/netfilter.h:306 net/ipv6/ip6_output.c:248)\n ip6_send_skb (net/ipv6/ip6_output.c:1983)\n rawv6_sendmsg (net/ipv6/raw.c:588 net/ipv6/raw.c:918)\n __sys_sendto (net/socket.c:714 (discriminator 1) net/socket.c:729 (discriminator 1) net/socket.c:2228 (discriminator 1))\n __x64_sys_sendto (net/socket.c:2231)\n do_syscall_64 (arch/x86/entry/syscall_64.c:63 (discriminator 1) arch/x86/entry/syscall_64.c:94 (discriminator 1))\n entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)\nRIP: 0033:0x7f68cffb2a06\nCode: 5d e8 41 8b 93 08 03 00 00 59 5e 48 83 f8 fc 75 19 83 e2 39 83 fa 08 75 11 e8 26 ff ff ff 66 0f 1f 44 00 00 48 8b 45 10 0f 05 <48> 8b 5d f8 c9 c3 0f 1f 40 00 f3 0f 1e fa 55 48 89 e5 48 83 ec 08\nRSP: 002b:00007ffefb7c53d0 EFLAGS: 00000202 ORIG_RAX: 000000000000002c\nRAX: ffffffffffffffda RBX: 0000564cd69f10a0 RCX: 00007f68cffb2a06\nRDX: 0000000000000040 RSI: 0000564cd69f10a4 RDI: 0000000000000003\nRBP: 00007ffefb7c53f0 R08: 0000564cd6a032ac R09: 000000000000001c\nR10: 0000000000000000 R11: 0000000000000202 R12: 0000564cd69f10a4\nR13: 0000000000000040 R14: 00007ffefb7c66e0 R15: 0000564cd69f10a0\n \n\nAllocated by task 1543:\n kasan_save_stack (mm/kasan/common.c:48)\n kasan_save_track (mm/kasan/common.c:60 (discriminator 1) mm/kasan/common.c:69 (discriminator 1))\n __kasan_slab_alloc (mm/kasan/common.c:319 mm/kasan/common.c:345)\n kmem_cache_alloc_node_noprof (./include/linux/kasan.h:250 mm/slub.c:4148 mm/slub.c:4197 mm/slub.c:4249)\n kmalloc_reserve (net/core/skbuff.c:581 (discriminator 88))\n __alloc_skb (net/core/skbuff.c:669)\n __ip6_append_data (net/ipv6/ip6_output.c:1672 (discriminator 1))\n ip6_\n---truncated---"
}
],
"metrics": [
{
"cvssV3_1": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"baseScore": 9.8,
"baseSeverity": "CRITICAL"
},
"scenarios": [
{
"lang": "en",
"value": "AV:N - The vulnerable function is reached from `rpl_input()` via `lwtunnel_input()` off `ipv6_rcv()`, i.e. driven purely by IPv6 packets received from a remote peer on a node with an `encap rpl` route (the KASAN stack confirms the `ipv6_rcv` → `lwtunnel_input` → `rpl_input` path). No local access is needed.\nAC:L - `skb_cow_head()` unconditionally reallocates whenever the compressed SRH plus link-layer overhead exceeds the skb's headroom — which a normal multi-segment RPL route always does — or whenever the skb header is cloned, so every matching packet trips the use-after-free with no race to win and no attacker-uncontrollable memory layout requirement.\nPR:N - The attacker only needs to send an IPv6 packet toward the RPL-routed prefix; there is no authentication, credential, or capability check anywhere on the receive path. The route configuration is victim-side administrative state, not a privilege the attacker must hold.\nUI:N - Processing happens in softirq context during normal packet reception and forwarding; no action by any local user or administrator is required at exploitation time.\nS:U - The freed memory and the resulting corruption are both within the kernel's own security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - Up to 40 bytes of freed slab memory are copied into the outgoing packet header, and roughly 21 of those bytes (traffic class, flow label, hop limit, and the entire 16-byte source address) survive to be transmitted on the wire, giving a directly observable kernel heap disclosure; the general use-after-free read primitive over attacker-groomable slab contents also warrants High.\nI:H - The use-after-free lets reallocated, attacker-sprayed heap contents dictate the constructed IPv6 header of a forwarded packet, and per kernel UAF guidance such freed-object reuse is treated as exploitable for heap manipulation and control-flow corruption rather than a benign read.\nA:H - Reading a freed skb head can hit poisoned, reallocated, or unmapped memory and oopses immediately under KASAN/debug allocators, and the resulting malformed headers occur in softirq context on the forwarding path — any such crash panics the router."
}
]
}
],
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{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "unaffected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"net/ipv6/rpl_iptunnel.c"
],
"versions": [
{
"version": "a7a29f9c361f8542604ef959ae6627f423b7a412",
"lessThan": "c09e21dfc08d8afb92d9ea3bee3457adbe3ef297",
"status": "affected",
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{
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{
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{
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"lessThan": "034b428aa3583373a5a20b1c5931bb2b3cae1f36",
"status": "affected",
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{
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{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "affected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"net/ipv6/rpl_iptunnel.c"
],
"versions": [
{
"version": "5.7",
"status": "affected"
},
{
"version": "0",
"lessThan": "5.7",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "5.10.241",
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "5.15.190",
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.1.147",
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.6.100",
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.12.40",
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.15.8",
"lessThanOrEqual": "6.15.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.16",
"lessThanOrEqual": "*",
"status": "unaffected",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
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"operator": "OR",
"negate": false,
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"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "5.7",
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},
{
"vulnerable": true,
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},
{
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"references": [
{
"url": "https://git.kernel.org/stable/c/c09e21dfc08d8afb92d9ea3bee3457adbe3ef297"
},
{
"url": "https://git.kernel.org/stable/c/8ba6c2362b85089b8972ac5f20b24fc71a4b8ffc"
},
{
"url": "https://git.kernel.org/stable/c/e8101506ab86dd78f823b7028f2036a380f3a12a"
},
{
"url": "https://git.kernel.org/stable/c/62dcd9d6e61c39122d2f251a26829e2e55b0a11d"
},
{
"url": "https://git.kernel.org/stable/c/06ec83b6c792fde1f710c1de3e836da6e257c4c4"
},
{
"url": "https://git.kernel.org/stable/c/034b428aa3583373a5a20b1c5931bb2b3cae1f36"
},
{
"url": "https://git.kernel.org/stable/c/b640daa2822a39ff76e70200cb2b7b892b896dce"
}
],
"title": "rpl: Fix use-after-free in rpl_do_srh_inline().",
"x_generator": {
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"adp": [
{
"title": "CVE Program Container",
"references": [
{
"url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html"
},
{
"url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html"
}
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"providerMetadata": {
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"shortName": "CVE",
"dateUpdated": "2025-11-03T17:38:42.878Z"
}
}
]
}
}