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CVE.org (no NVD analysis yet)· CNA Linux

CVE-2026-98303: ipv4: icmp: reject RTN_UNREACHABLE input routes in icmp_route_lookup

Noroxi assessment

Priority: Monitor (action score 0/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.18% (FIRST EPSS).
  • Fixed version: Linux Linux 06083cea4a3b95f5ebc85312f97d7086e6c9e782, 1af2d87964d87ba7626d96928d68c09158b5a223, 2998147b59c9df0a51477c7a6b3d1f0ba3127dd4; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 6.6.158.1-1.

Low priority for now. Upgrade to Linux Linux 06083cea4a3b95f5ebc85312f97d7086e6c9e782, 1af2d87964d87ba7626d96928d68c09158b5a223, 2998147b59c9df0a51477c7a6b3d1f0ba3127dd4; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 6.6.158.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

—No exploit Fix available
Published
Oct 6, 2026
Updated
Oct 19, 2026
EPSS
0.1% · 7th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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Noroxi analysis

What does it mean in your environment?

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 2.6.25affected
    • 8b7817f3a959ed99d7443afc12f78a7e1fcc2063 and later · before 06083cea4a3b95f5ebc85312f97d7086e6c9e782affected · git
    • 8b7817f3a959ed99d7443afc12f78a7e1fcc2063 and later · before 83aa83f81a8fec30ff5372dee60b2f0561bcb2caaffected · git
    • 8b7817f3a959ed99d7443afc12f78a7e1fcc2063 and later · before cac69c50716c712ef0114837c9427da66066124caffected · git
    • 8b7817f3a959ed99d7443afc12f78a7e1fcc2063 and later · before 1af2d87964d87ba7626d96928d68c09158b5a223affected · git
    • 8b7817f3a959ed99d7443afc12f78a7e1fcc2063 and later · before fda3000147dc96c75ba162f680bec0a9fecf3037affected · git
    • 8b7817f3a959ed99d7443afc12f78a7e1fcc2063 and later · before 2998147b59c9df0a51477c7a6b3d1f0ba3127dd4affected · git
    • before 2.6.25not affected · semver
    • 6.1.189 and later · up to and including 6.1.*not affected · semver
    • 6.6.158 and later · up to and including 6.6.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.190-16.1.190-1
Debian:12linux-6.12before 6.12.113-1~deb12u16.12.113-1~deb12u1
Debian:13linuxbefore 6.12.113-16.12.113-1
Debian:14linuxbefore 7.2.8-17.2.8-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-98301Oct 6, 2026 · net: bridge: mst: move switchdev call outside rcu
    0Monitor
  • ← EarlierCVE-2026-98302Oct 6, 2026 · net: fddi: skfp: fix NULL deref when setting the MAC address while down
    0Monitor
  • Later →CVE-2026-98304Oct 6, 2026 · net: bcmgenet: restore the hardware filters on open
    0Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux06083cea4a3b95f5ebc85312f97d7086e6c9e782Vendor (CNA)
Linux Linux1af2d87964d87ba7626d96928d68c09158b5a223Vendor (CNA)
Linux Linux2998147b59c9df0a51477c7a6b3d1f0ba3127dd4Vendor (CNA)
Linux Linux83aa83f81a8fec30ff5372dee60b2f0561bcb2caVendor (CNA)
Linux Linuxcac69c50716c712ef0114837c9427da66066124cVendor (CNA)
Linux Linuxfda3000147dc96c75ba162f680bec0a9fecf3037Vendor (CNA)
azl3 kernel 6.6.157.1-1 on Azure Linux 3.06.6.158.1-1 · Release NotesMicrosoft (MSRC)
debian:linux6.1.190-1 · Debian:12Package registry (OSV)
debian:linux6.12.113-1 · Debian:13Package registry (OSV)
debian:linux7.2.8-1 · Debian:14Package registry (OSV)
debian:linux-6.126.12.113-1~deb12u1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. Fix recordedsame day
  3. TodayNov 9, 2026+34 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Exploit maturity— → none
  2. Fix✗ → ✓

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References

Show all references (5 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records