CVSS 3.1 base metricsRed raises the risk · green lowers it
Attack vector
NetworkAV:N
Attack complexity
LowAC:L
Privileges required
NonePR:N
User interaction
NoneUI:N
Scope
UnchangedS:U
Confidentiality
HighC:H
Integrity
HighI:H
Availability
HighA:H
Updates that fix it
0 KBs
No KB listed
No KB update is listed in the collected MSRC record. Check the MSRC advisory for product releases and other remedies.
Affected products
Open Source Software
1 affected product
azl3 kernel 6.6.157.1-1 on Azure Linux 3.0
What changed
Detection template: Unknown: detection-template evidence is incomplete or retained → No Nuclei template listed
Detection template: No Nuclei template listed → Unknown: detection-template evidence is incomplete or retained
Detection template: Unknown: detection-template evidence is incomplete or retained → No Nuclei template listed
Detection template: No Nuclei template listed → Unknown: detection-template evidence is incomplete or retained
Detection template: No Nuclei template listed · Customer action: Required: apply the update → Required: follow the MSRC remediation guidance · Public disclosure: No → Unknown: not stated by MSRC · Exploitation detected: Not reported by MSRC → Unknown: not stated by MSRC
Detection template: Unknown: exploit-code evidence is incomplete or retained → No Nuclei template listed · CISA KEV: Unknown: catalog evidence is incomplete or retained → Not listed in the collected catalog
Detection template: No Nuclei template listed → Unknown: exploit-code evidence is incomplete or retained · CISA KEV: Not listed in the collected catalog → Unknown: catalog evidence is incomplete or retained
Page history
Changes are dated when recorded; day views use the last saved version from that UTC day, and citations stay fixed.
CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.
No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.
cve-program · CVE-2026-98303
Published
ipv4: icmp: reject RTN_UNREACHABLE input routes in icmp_route_lookup
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.
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