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CVE-2021-47309

7.8 · HIGH

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_…

Published May 21, 2024CWE-125EPSS 0.25%

Overview

CVE-2021-47309 is a high-severity vulnerability. It was published on May 21, 2024 and has a CVSS 3.1 base score of 7.8 (HIGH).

This vulnerability has a CVSS 3.1 base score of 7.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

Technical 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_

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

Refgit.kernel.org/stable/c/2179d96ec702cc33ead02a9ce40ece599b8538c5Refgit.kernel.org/stable/c/67a9c94317402b826fc3db32afc8f39336803d97Refgit.kernel.org/stable/c/83bdcfbd968bcc91a0632b7b625e4a9b0cba5e0dRefgit.kernel.org/stable/c/8aa13a86964cdec4fd969ef677c6614ff068641aRefgit.kernel.org/stable/c/8bb1589c89e61e3b182dd546f1021928ebb5c2a6Refgit.kernel.org/stable/c/a915379594f1e045421635c6316d8f3ffa018c58Refgit.kernel.org/stable/c/b61d327cd3cc5ea591f3bf751dd11e034f388bb5Refgit.kernel.org/stable/c/e7f3c9df40515a6c6b46f36c4c94cf48a043f887Refgit.kernel.org/stable/c/2179d96ec702cc33ead02a9ce40ece599b8538c5Refgit.kernel.org/stable/c/67a9c94317402b826fc3db32afc8f39336803d97

How CyberStrike helps

Frequently asked questions

What is CVE-2021-47309?

CVE-2021-47309 is a high-severity vulnerability. It was published on May 21, 2024 and has a CVSS 3.1 base score of 7.8 (HIGH).

How severe is CVE-2021-47309?

This vulnerability has a CVSS 3.1 base score of 7.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2021-47309?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2021-47309?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-47309 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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