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CVE Record

CVE-2024-56647: net: Fix icmp host relookup triggering ip_rt_bug

In the Linux kernel, the following vulnerability has been resolved: net: Fix icmp host relookup triggering ip_rt_bug arp link failure may trigger ip_rt_bug while xfrm enabled, call trace is: WARNING: CPU: 0 PID: 0 at net/ipv4/route.c:1241 ip_rt_bug+0x14/0x20 Modules linked in: CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.12.0-rc6-00077-g2e1b3cc9d7f7 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 RIP: 0010:ip_rt_bug+0x14/0x20 Call Trace: <IRQ> ip_send_skb+0x14/0x40 __icmp_send+0x42d/0x6a0 ipv4_link_failure+0xe2/0x1d0 arp_error_report+0x3c/0x50 neigh_invalidate+0x8d/0x100 neigh_timer_handler+0x2e1/0x330 call_timer_fn+0x21/0x120 __run_timer_base.part.0+0x1c9/0x270 run_timer_softirq+0x4c/0x80 handle_softirqs+0xac/0x280 irq_exit_rcu+0x62/0x80 sysvec_apic_timer_interrupt+0x77/0x90 The script below reproduces this scenario: ip xfrm policy add src 0.0.0.0/0 dst 0.0.0.0/0 \ dir out priority 0 ptype main flag localok icmp ip l a veth1 type veth ip a a 192.168.141.111/24 dev veth0 ip l s veth0 up ping 192.168.141.155 -c 1 icmp_route_lookup() create input routes for locally generated packets while xfrm relookup ICMP traffic.Then it will set input route (dst->out = ip_rt_bug) to skb for DESTUNREACH. For ICMP err triggered by locally generated packets, dst->dev of output route is loopback. Generally, xfrm relookup verification is not required on loopback interfaces (net.ipv4.conf.lo.disable_xfrm = 1). Skip icmp relookup for locally generated packets to fix it.

MediumCVSS 5.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This Linux kernel flaw can trigger a kernel routing bug during ICMP error handling when XFRM/IPsec processing is involved. The practical impact is availability: a local, low-privileged actor may be able to cause a disruptive kernel warning or failure path. There is no source evidence of data theft, privilege escalation, or active exploitation.

Executive priority

Patch during the next normal kernel maintenance window, sooner for shared Linux platforms or systems relying on IPsec/XFRM. The urgency is moderate because exploitation requires local access, but the impact can affect availability.

Technical view

The issue is in IPv4 ICMP route lookup. Locally generated packet failures can be reprocessed through XFRM, assigning an input route with ip_rt_bug as output handling for destination-unreachable traffic. The kernel fix skips ICMP relookup for locally generated packets. CVSS is 5.5, local attack vector, low privileges, high availability impact.

Likely exposure

Exposure is mainly Linux systems running affected kernel builds where local users or workloads can exercise networking paths involving XFRM/IPsec and ICMP error generation. Internet-only exposure is not supported by the supplied sources because the CVSS vector is local.

Exploitation context

The source bundle includes a local reproduction scenario, but no KEV listing and no cited public evidence of active exploitation. Treat this as a reliability and denial-of-service risk for multi-user, container-hosting, or sensitive Linux infrastructure rather than a remote compromise issue.

Researcher notes

The provided evidence supports a local availability flaw in Linux IPv4 ICMP/XFRM routing behavior. Affected-version data in the bundle is not distribution-specific, so package-level exposure requires vendor mapping. No exploit-in-the-wild evidence is provided.

Mitigation direction

  • Apply Linux kernel updates containing the referenced stable fixes.
  • Check distribution advisories for exact package versions and backports.
  • Prioritize shared hosts, container platforms, and systems using XFRM/IPsec.
  • Restrict untrusted local shell or workload access where patching is delayed.
  • Monitor kernel logs for route warnings or ICMP/XFRM-related failures.

Validation and detection

  • Inventory Linux kernel versions across affected fleets.
  • Confirm vendor packages include the referenced stable kernel fixes.
  • Review whether XFRM/IPsec is enabled or used on exposed systems.
  • Check kernel logs for ip_rt_bug warnings or related call traces.
  • Validate remediation through approved regression testing, not public reproducer use.
Prepared
Confidence
high
Sources
6

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2024-56647 mapping review

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
5.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
3Timeline events
1ADP providers
5Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
5.5CVSS 3.1MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H1.83.6CISA-ADP

Vulnerability scoring details

Base CVSS 3.1 score

5.5Medium
CVSS 3.1 vector shape for CVE-2024-56647Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
cvssV3_1other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux8b7817f3a959ed99d7443afc12f78a7e1fcc2063, 8b7817f3a959ed99d7443afc12f78a7e1fcc2063, 8b7817f3a959ed99d7443afc12f78a7e1fcc2063, 8b7817f3a959ed99d7443afc12f78a7e1fcc2063unaffected
LinuxLinux2.6.25, 0, 6.1.175, 6.6.140, 6.12.5, 6.13affected
Weakness

CWE details

No CWE listed

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