ipv4: icmp: reject RTN_UNREACHABLE input routes in icmp_route_lookup
Summary
| CVE | CVE-2026-98303 |
|---|---|
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-10-06 09:18:21 UTC |
| Updated | 2026-10-19 10:18:32 UTC |
| 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. |
Risk And Classification
EPSS: 0.001800000 probability, percentile 0.069220000 (date 2026-10-06)
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Linux | Linux | affected 8b7817f3a959ed99d7443afc12f78a7e1fcc2063 06083cea4a3b95f5ebc85312f97d7086e6c9e782 git | Not specified |
| CNA | Linux | Linux | affected 8b7817f3a959ed99d7443afc12f78a7e1fcc2063 83aa83f81a8fec30ff5372dee60b2f0561bcb2ca git | Not specified |
| CNA | Linux | Linux | affected 8b7817f3a959ed99d7443afc12f78a7e1fcc2063 cac69c50716c712ef0114837c9427da66066124c git | Not specified |
| CNA | Linux | Linux | affected 8b7817f3a959ed99d7443afc12f78a7e1fcc2063 1af2d87964d87ba7626d96928d68c09158b5a223 git | Not specified |
| CNA | Linux | Linux | affected 8b7817f3a959ed99d7443afc12f78a7e1fcc2063 fda3000147dc96c75ba162f680bec0a9fecf3037 git | Not specified |
| CNA | Linux | Linux | affected 8b7817f3a959ed99d7443afc12f78a7e1fcc2063 2998147b59c9df0a51477c7a6b3d1f0ba3127dd4 git | Not specified |
| CNA | Linux | Linux | affected 2.6.25 | Not specified |
| CNA | Linux | Linux | unaffected 2.6.25 semver | Not specified |
| CNA | Linux | Linux | unaffected 6.1.189 6.1.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.6.158 6.6.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.12.112 6.12.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.18.54 6.18.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.2.8 7.2.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.3 * original_commit_for_fix | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| git.kernel.org/stable/c/1af2d87964d87ba7626d96928d68c09158b5a223 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/2998147b59c9df0a51477c7a6b3d1f0ba3127dd4 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/fda3000147dc96c75ba162f680bec0a9fecf3037 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/83aa83f81a8fec30ff5372dee60b2f0561bcb2ca | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/06083cea4a3b95f5ebc85312f97d7086e6c9e782 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/cac69c50716c712ef0114837c9427da66066124c | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.