Executive Summary

Informations
Name CVE-2024-56751 First vendor Publication 2024-12-29
Vendor Cve Last vendor Modification 2025-01-06

Security-Database Scoring CVSS v3

Cvss vector : CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Overall CVSS Score 5.5
Base Score 5.5 Environmental Score 5.5
impact SubScore 3.6 Temporal Score 5.5
Exploitabality Sub Score 1.8
 
Attack Vector Local Attack Complexity Low
Privileges Required Low User Interaction None
Scope Unchanged Confidentiality Impact None
Integrity Impact None Availability Impact High
Calculate full CVSS 3.0 Vectors scores

Security-Database Scoring CVSS v2

Cvss vector :
Cvss Base Score N/A Attack Range N/A
Cvss Impact Score N/A Attack Complexity N/A
Cvss Expoit Score N/A Authentication N/A
Calculate full CVSS 2.0 Vectors scores

Detail

In the Linux kernel, the following vulnerability has been resolved:

ipv6: release nexthop on device removal

The CI is hitting some aperiodic hangup at device removal time in the pmtu.sh self-test:

unregister_netdevice: waiting for veth_A-R1 to become free. Usage count = 6 ref_tracker: veth_A-R1@ffff888013df15d8 has 1/5 users at
dst_init+0x84/0x4a0
dst_alloc+0x97/0x150
ip6_dst_alloc+0x23/0x90
ip6_rt_pcpu_alloc+0x1e6/0x520
ip6_pol_route+0x56f/0x840
fib6_rule_lookup+0x334/0x630
ip6_route_output_flags+0x259/0x480
ip6_dst_lookup_tail.constprop.0+0x5c2/0x940
ip6_dst_lookup_flow+0x88/0x190
udp_tunnel6_dst_lookup+0x2a7/0x4c0
vxlan_xmit_one+0xbde/0x4a50 [vxlan]
vxlan_xmit+0x9ad/0xf20 [vxlan]
dev_hard_start_xmit+0x10e/0x360
__dev_queue_xmit+0xf95/0x18c0
arp_solicit+0x4a2/0xe00
neigh_probe+0xaa/0xf0

While the first suspect is the dst_cache, explicitly tracking the dst owing the last device reference via probes proved such dst is held by the nexthop in the originating fib6_info.

Similar to commit f5b51fe804ec ("ipv6: route: purge exception on removal"), we need to explicitly release the originating fib info when disconnecting a to-be-removed device from a live ipv6 dst: move the fib6_info cleanup into ip6_dst_ifdown().

Tested running:

./pmtu.sh cleanup_ipv6_exception

in a tight loop for more than 400 iterations with no spat, running an unpatched kernel I observed a splat every ~10 iterations.

Original Source

Url : http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-56751

CPE : Common Platform Enumeration

TypeDescriptionCount
Application 8
Os 3667

Sources (Detail)

https://git.kernel.org/stable/c/0e4c6faaef8a24b762a24ffb767280e263ef8e10
https://git.kernel.org/stable/c/43e25adc80269f917d2a195f0d59f74cdd182955
https://git.kernel.org/stable/c/a3c3f8a4d025acc8c857246ec2b812c59102487a
https://git.kernel.org/stable/c/b2f26a27ea3f72f75d18330f76f5d1007c791848
https://git.kernel.org/stable/c/eb02688c5c45c3e7af7e71f036a7144f5639cbfe
Source Url

Alert History

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Date Informations
2025-01-08 00:20:38
  • Multiple Updates
2025-01-07 03:08:07
  • Multiple Updates
2025-01-07 00:20:34
  • Multiple Updates
2025-01-06 21:20:29
  • Multiple Updates
2024-12-29 17:20:29
  • First insertion