{"id":"CVE-2024-56647","url":"https://www.cyber-defence.io/tools/cve/CVE-2024-56647","generatedAt":"2026-10-28T02:21:01.634Z","title":"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…","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: Fix icmp host relookup triggering ip_rt_bug\n\narp link failure may trigger ip_rt_bug while xfrm enabled, call trace is:\n\nWARNING: CPU: 0 PID: 0 at net/ipv4/route.c:1241 ip_rt_bug+0x14/0x20\nModules linked in:\nCPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.12.0-rc6-00077-g2e1b3cc9d7f7\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996),\nBIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014\nRIP: 0010:ip_rt_bug+0x14/0x20\nCall Trace:\n <IRQ>\n ip_send_skb+0x14/0x40\n __icmp_send+0x42d/0x6a0\n ipv4_link_failure+0xe2/0x1d0\n arp_error_report+0x3c/0x50\n neigh_invalidate+0x8d/0x100\n neigh_timer_handler+0x2e1/0x330\n call_timer_fn+0x21/0x120\n __run_timer_base.part.0+0x1c9/0x270\n run_timer_softirq+0x4c/0x80\n handle_softirqs+0xac/0x280\n irq_exit_rcu+0x62/0x80\n sysvec_apic_timer_interrupt+0x77/0x90\n\nThe script below reproduces this scenario:\nip xfrm policy add src 0.0.0.0/0 dst 0.0.0.0/0 \\\n\tdir out priority 0 ptype main flag localok icmp\nip l a veth1 type veth\nip a a 192.168.141.111/24 dev veth0\nip l s veth0 up\nping 192.168.141.155 -c 1\n\nicmp_route_lookup() create input routes for locally generated packets\nwhile xfrm relookup ICMP traffic.Then it will set input route\n(dst->out = ip_rt_bug) to skb for DESTUNREACH.\n\nFor ICMP err triggered by locally generated packets, dst->dev of output\nroute is loopback. Generally, xfrm relookup verification is not required\non loopback interfaces (net.ipv4.conf.lo.disable_xfrm = 1).\n\nSkip icmp relookup for locally generated packets to fix it.","published":"2024-12-27T15:15:24.000Z","lastModified":"2026-10-15T02:17:08.000Z","status":"Modified","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","cvss":{"version":"3.1","score":5.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"},"cwe":[],"affected":["linux/linux kernel"],"epss":{"score":0.00223,"percentile":0.12818,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.22%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://git.kernel.org/stable/c/9545011e7b2a8fc0cbd6e387a09f12cd41d7d82f","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/c44daa7e3c73229f7ac74985acb8c7fb909c4e0a","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/d50981aaaefc3b04490fbc8274d37881a2b1b112","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/da54b3039d436227deebbc202cefea63bd318a38","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-784472.html","source":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2024-56647","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}