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CVE-2021-47247

7.8 · HIGH

In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: Fix use-after-free of encap entry in neigh update handler Function mlx5e_rep_neigh_update() wasn't updated to accomm…

Published May 21, 2024CWE-416EPSS 0.23%

Overview

CVE-2021-47247 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/mlx5e: Fix use-after-free of encap entry in neigh update handler

Function mlx5e_rep_neigh_update() wasn't updated to accommodate rtnl lock

removal from TC filter update path and properly handle concurrent encap

entry insertion/deletion which can lead to following use-after-free:

[23827.464923] ==================================================================

[23827.469446] BUG: KASAN: use-after-free in mlx5e_encap_take+0x72/0x140 [mlx5_core]

[23827.470971] Read of size 4 at addr ffff8881d132228c by task kworker/u20:6/21635

[23827.472251]

[23827.472615] CPU: 9 PID: 21635 Comm: kworker/u20:6 Not tainted 5.13.0-rc3+ #5

[23827.473788] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014

[23827.475639] Workqueue: mlx5e mlx5e_rep_neigh_update [mlx5_core]

[23827.476731] Call Trace:

[23827.477260] dump_stack+0xbb/0x107

[23827.477906] print_address_

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/0d1e7a7964ce6abb28883a3906bbc20fe0009f03Refgit.kernel.org/stable/c/b6447b72aca571632e71bb73a797118d5ce46a93Refgit.kernel.org/stable/c/fb1a3132ee1ac968316e45d21a48703a6db0b6c3Refgit.kernel.org/stable/c/b6447b72aca571632e71bb73a797118d5ce46a93Refgit.kernel.org/stable/c/fb1a3132ee1ac968316e45d21a48703a6db0b6c3Reflists.debian.org/debian-lts-announce/2025/05/msg00030.html

How CyberStrike helps

Frequently asked questions

What is CVE-2021-47247?

CVE-2021-47247 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-2021-47247?

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-2021-47247?

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-2021-47247?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-47247 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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