CVE-2026-98303
Full vulnerability record from the local CVENow database.
Description
In the Linux kernel, the following vulnerability has been resolved: ipv4: icmp: reject RTN_UNREACHABLE input routes in icmp_route_lookup When the forward output route cannot be used in icmp_route_lookup(), it enters the "reverse path" and calls ip_route_input() on fl4_dec.daddr, the original packet's source address. ip_route_input() only returns an error for truly invalid packets. For unreachable addresses it will succeed and return an input route whose dst.output is set to ip_rt_bug(). The existing check only rejects RTN_LOCAL routes, so the RTN_UNREACHABLE route types can still be returned and later used for output, syzkaller triggering a WARN_ON_ONCE() in ip_rt_bug() as bellow: ------------[ cut here ]------------ WARNING: net/ipv4/route.c:1273 at ip_rt_bug+0x14/0x20 RIP: 0010:ip_rt_bug+0x14/0x20 Call Trace: ip_push_pending_frames+0xfa/0x100 __icmp_send+0x905/0xf10 ip_options_compile+0xc0/0xd0 ip_rcv_finish_core+0x321/0xae0 ip_rcv+0x1de/0x260 __netif_receive_skb_one_core+0x11a/0x130 netif_receive_skb+0x7b/0x260 tun_get_user+0x11bf/0x1c10 ------------[ cut here ]------------ Reject input route that is RTN_UNREACHABLE to fix it. The net warning is only printed for RTN_LOCAL, as RTN_UNREACHABLE is not the result of a race condition.
View original CVE JSON
{
"id": "CVE-2026-98303",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-10-06T09:18:21.370",
"lastModified": "2026-10-19T10:18:32.300",
"vulnStatus": "Received",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv4: icmp: reject RTN_UNREACHABLE input routes in icmp_route_lookup\n\nWhen the forward output route cannot be used in icmp_route_lookup(),\nit enters the \"reverse path\" and calls ip_route_input() on fl4_dec.daddr,\nthe original packet's source address.\n\nip_route_input() only returns an error for truly invalid packets. For\nunreachable addresses it will succeed and return an input route whose\ndst.output is set to ip_rt_bug(). The existing check only rejects\nRTN_LOCAL routes, so the RTN_UNREACHABLE route types can still be returned\nand later used for output, syzkaller triggering a WARN_ON_ONCE()\nin ip_rt_bug() as bellow:\n\n ------------[ cut here ]------------\n WARNING: net/ipv4/route.c:1273 at ip_rt_bug+0x14/0x20\n RIP: 0010:ip_rt_bug+0x14/0x20\n Call Trace:\n ip_push_pending_frames+0xfa/0x100\n __icmp_send+0x905/0xf10\n ip_options_compile+0xc0/0xd0\n ip_rcv_finish_core+0x321/0xae0\n ip_rcv+0x1de/0x260\n __netif_receive_skb_one_core+0x11a/0x130\n netif_receive_skb+0x7b/0x260\n tun_get_user+0x11bf/0x1c10\n ------------[ cut here ]------------\n\nReject input route that is RTN_UNREACHABLE to fix it. The net warning\nis only printed for RTN_LOCAL, as RTN_UNREACHABLE is not the result of\na race condition."
}
],
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "unaffected",
"programFiles": [
"net/ipv4/icmp.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "8b7817f3a959ed99d7443afc12f78a7e1fcc2063",
"lessThan": "06083cea4a3b95f5ebc85312f97d7086e6c9e782",
"versionType": "git",
"status": "affected"
},
{
"version": "8b7817f3a959ed99d7443afc12f78a7e1fcc2063",
"lessThan": "83aa83f81a8fec30ff5372dee60b2f0561bcb2ca",
"versionType": "git",
"status": "affected"
},
{
"version": "8b7817f3a959ed99d7443afc12f78a7e1fcc2063",
"lessThan": "cac69c50716c712ef0114837c9427da66066124c",
"versionType": "git",
"status": "affected"
},
{
"version": "8b7817f3a959ed99d7443afc12f78a7e1fcc2063",
"lessThan": "1af2d87964d87ba7626d96928d68c09158b5a223",
"versionType": "git",
"status": "affected"
},
{
"version": "8b7817f3a959ed99d7443afc12f78a7e1fcc2063",
"lessThan": "fda3000147dc96c75ba162f680bec0a9fecf3037",
"versionType": "git",
"status": "affected"
},
{
"version": "8b7817f3a959ed99d7443afc12f78a7e1fcc2063",
"lessThan": "2998147b59c9df0a51477c7a6b3d1f0ba3127dd4",
"versionType": "git",
"status": "affected"
}
]
},
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "affected",
"programFiles": [
"net/ipv4/icmp.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "2.6.25",
"status": "affected"
},
{
"version": "0",
"lessThan": "2.6.25",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.1.189",
"lessThanOrEqual": "6.1.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.6.158",
"lessThanOrEqual": "6.6.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.12.112",
"lessThanOrEqual": "6.12.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.18.54",
"lessThanOrEqual": "6.18.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.2.8",
"lessThanOrEqual": "7.2.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.3",
"lessThanOrEqual": "*",
"versionType": "original_commit_for_fix",
"status": "unaffected"
}
]
}
]
}
],
"metrics": {},
"references": [
{
"url": "https://git.kernel.org/stable/c/06083cea4a3b95f5ebc85312f97d7086e6c9e782",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/1af2d87964d87ba7626d96928d68c09158b5a223",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/2998147b59c9df0a51477c7a6b3d1f0ba3127dd4",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/83aa83f81a8fec30ff5372dee60b2f0561bcb2ca",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/cac69c50716c712ef0114837c9427da66066124c",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/fda3000147dc96c75ba162f680bec0a9fecf3037",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
]
}