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ipv4: icmp: reject RTN_UNREACHABLE input routes in icmp_route_lookup

Type: advisorySource: Official CVE List1 source record

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.

Announced Source revision 1
Original source ↗

CVE-2026-98303

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-98303

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "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"
      }
    ],
    "programFiles": [
      "net/ipv4/icmp.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "2.6.25"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "2.6.25",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.1.189",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.158",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.112",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.54",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.2.8",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "net/ipv4/icmp.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-98303

Source reference: /cveMetadata/cveId

Publisher severity

No explicit severity was provided.

Event
#38380 · Revision 1
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Publisher date
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