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CVE PROGRAM SOURCE RECORDUnscored

CVE-2026-98303

ipv4: icmp: reject RTN_UNREACHABLE input routes in icmp_route_lookup

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Status
Published
Published
Updated
Assigning organization
Linux

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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 8b7817f3a959ed99d7443afc12f78a7e1fcc2063 to < 06083cea4a3b95f5ebc85312f97d7086e6c9e782affected
  • 8b7817f3a959ed99d7443afc12f78a7e1fcc2063 to < 83aa83f81a8fec30ff5372dee60b2f0561bcb2caaffected
  • 8b7817f3a959ed99d7443afc12f78a7e1fcc2063 to < cac69c50716c712ef0114837c9427da66066124caffected
  • 8b7817f3a959ed99d7443afc12f78a7e1fcc2063 to < 1af2d87964d87ba7626d96928d68c09158b5a223affected
  • 8b7817f3a959ed99d7443afc12f78a7e1fcc2063 to < fda3000147dc96c75ba162f680bec0a9fecf3037affected
  • 8b7817f3a959ed99d7443afc12f78a7e1fcc2063 to < 2998147b59c9df0a51477c7a6b3d1f0ba3127dd4affected

Linux Linux

Default version status: affected

  • 2.6.25affected
  • 0 to < 2.6.25unaffected
  • 6.1.189 to ≤ 6.1.*unaffected
  • 6.6.158 to ≤ 6.6.*unaffected
  • 6.12.112 to ≤ 6.12.*unaffected
  • 6.18.54 to ≤ 6.18.*unaffected
  • 7.2.8 to ≤ 7.2.*unaffected
  • 7.3 to ≤ *unaffected

References