CVE-2021-47309

net: validate lwtstate->data before returning from skb_tunnel_info()

HIGH

7.1

CVSS Score

Published: May 21, 2024 at 02:35 PM UTC

Updated: August 5, 2026 at 09:24 AM UTC

1 product affected across 1 vendorLinux Kernel

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Severity

HIGH7.1

Exploit prediction

EPSS 0.3%

SSVC

No known exploit

Description

In the Linux kernel, the following vulnerability has been resolved: net: validate lwtstate->data before returning from skb_tunnel_info() skb_tunnel_info() returns pointer of lwtstate->data as ip_tunnel_info type without validation. lwtstate->data can have various types such as mpls_iptunnel_encap, etc and these are not compatible. So skb_tunnel_info() should validate before returning that pointer. Splat looks like: BUG: KASAN: slab-out-of-bounds in vxlan_get_route+0x418/0x4b0 [vxlan] Read of size 2 at addr ffff888106ec2698 by task ping/811 CPU: 1 PID: 811 Comm: ping Not tainted 5.13.0+ #1195 Call Trace: dump_stack_lvl+0x56/0x7b print_address_description.constprop.8.cold.13+0x13/0x2ee ? vxlan_get_route+0x418/0x4b0 [vxlan] ? vxlan_get_route+0x418/0x4b0 [vxlan] kasan_report.cold.14+0x83/0xdf ? vxlan_get_route+0x418/0x4b0 [vxlan] vxlan_get_route+0x418/0x4b0 [vxlan] [ ... ] vxlan_xmit_one+0x148b/0x32b0 [vxlan] [ ... ] vxlan_xmit+0x25c5/0x4780 [vxlan] [ ... ] dev_hard_start_xmit+0x1ae/0x6e0 __dev_queue_xmit+0x1f39/0x31a0 [ ... ] neigh_xmit+0x2f9/0x940 mpls_xmit+0x911/0x1600 [mpls_iptunnel] lwtunnel_xmit+0x18f/0x450 ip_finish_output2+0x867/0x2040 [ ... ]

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Linux Kernel · Linux

95%

4.10 ≤ v < 4.14.2414.15 ≤ v < 4.19.1994.20 ≤ v < 5.4.1354.3 ≤ v < 4.14.2414.3 ≤ v < 4.19.1994.3 ≤ v < 4.4.2774.3 ≤ v < 4.9.2774.3 ≤ v < 5.10.534.3 ≤ v < 5.13.54.3 ≤ v < 5.144.3 ≤ v < 5.4.1354.5 ≤ v < 4.9.2775.11 ≤ v < 5.13.55.5 ≤ v < 5.10.535.14 rc161adedf3e3f1d3f032c5a6a299978d91eff6d555

Vendor states this is fixed in 2179d96ec702cc33ead02a9ce40ece599b8538c5 (fixed)

Vendor states this is fixed in 67a9c94317402b826fc3db32afc8f39336803d97 (fixed)

Vendor states this is fixed in 83bdcfbd968bcc91a0632b7b625e4a9b0cba5e0d (fixed)

Vendor states this is fixed in 8aa13a86964cdec4fd969ef677c6614ff068641a (fixed)

Vendor states this is fixed in 8bb1589c89e61e3b182dd546f1021928ebb5c2a6 (fixed)

Vendor states this is fixed in a915379594f1e045421635c6316d8f3ffa018c58 (fixed)

Vendor states this is fixed in b61d327cd3cc5ea591f3bf751dd11e034f388bb5 (fixed)

Vendor states this is fixed in e7f3c9df40515a6c6b46f36c4c94cf48a043f887 (fixed)

Vendor states this is fixed in 4.14.241 (unaffected)

Vendor states this is fixed in 4.19.199 (unaffected)

Vendor states this is fixed in 4.3 (unaffected)

Vendor states this is fixed in 4.4.277 (unaffected)