{"id":"CVE-2026-98303","title":"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\" …","summary":"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\" …","severity":"medium","vendor":"Linux","product":"Linux","affected":["Linux >= 8b7817f3a959ed99d7443afc12f78a7e1fcc2063 < 06083cea4a3b95f5ebc85312f97d7086e6c9e782","Linux >= 8b7817f3a959ed99d7443afc12f78a7e1fcc2063 < 83aa83f81a8fec30ff5372dee60b2f0561bcb2ca","Linux >= 8b7817f3a959ed99d7443afc12f78a7e1fcc2063 < cac69c50716c712ef0114837c9427da66066124c","Linux >= 8b7817f3a959ed99d7443afc12f78a7e1fcc2063 < 1af2d87964d87ba7626d96928d68c09158b5a223","Linux >= 8b7817f3a959ed99d7443afc12f78a7e1fcc2063 < fda3000147dc96c75ba162f680bec0a9fecf3037","Linux >= 8b7817f3a959ed99d7443afc12f78a7e1fcc2063 < 2998147b59c9df0a51477c7a6b3d1f0ba3127dd4","Linux 2.6.25"],"published":"2026-10-06","updated":"2026-10-06","sourceUpdated":"2026-10-06T09:18:21.370","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-98303","references":[{"url":"https://git.kernel.org/stable/c/06083cea4a3b95f5ebc85312f97d7086e6c9e782","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/1af2d87964d87ba7626d96928d68c09158b5a223","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/2998147b59c9df0a51477c7a6b3d1f0ba3127dd4","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/83aa83f81a8fec30ff5372dee60b2f0561bcb2ca","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/cac69c50716c712ef0114837c9427da66066124c","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/fda3000147dc96c75ba162f680bec0a9fecf3037","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98303.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-98303"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2546531"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-98303"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98303"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98303.mbox"}],"tags":["nvd","cve.org","csaf","vex","red-hat"],"ingestedAt":"2026-10-06T08:50:17.412Z","cvss":5.5,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","cvssSource":"vendor","cwe":["CWE-617"],"epss":0.0018,"epssPercentile":0.07535,"slug":"CVE-2026-98303","body":"## Overview\n\nIn 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, … · updated 2026-10-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98303.json)","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":218418,"id":"CVE-2026-98303","ts":1791533719535,"field":"cvss","old":null,"new":"5.5"},{"seq":218417,"id":"CVE-2026-98303","ts":1791533719535,"field":"severity","old":"none","new":"medium"}]}