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CVE-2021-47010

7.8 · HIGH

In the Linux kernel, the following vulnerability has been resolved: net: Only allow init netns to set default tcp cong to a restricted algo tcp_set_default_congestion_control() is netns-safe in t…

Published Feb 28, 2024CWE-400EPSS 0.26%

Overview

CVE-2021-47010 is a high-severity vulnerability. It was published on February 28, 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: Only allow init netns to set default tcp cong to a restricted algo

tcp_set_default_congestion_control() is netns-safe in that it writes

to &net->ipv4.tcp_congestion_control, but it also sets

ca->flags |= TCP_CONG_NON_RESTRICTED which is not namespaced.

This has the unintended side-effect of changing the global

net.ipv4.tcp_allowed_congestion_control sysctl, despite the fact that it

is read-only: 97684f0970f6 ("net: Make tcp_allowed_congestion_control

readonly in non-init netns")

Resolve this netns "leak" by only allowing the init netns to set the

default algorithm to one that is restricted. This restriction could be

removed if tcp_allowed_congestion_control were namespace-ified in the

future.

This bug was uncovered with

https://github.com/JonathonReinhart/linux-netns-sysctl-verify

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/6c1ea8bee75df8fe2184a50fcd0f70bf82986f42Refgit.kernel.org/stable/c/8d432592f30fcc34ef5a10aac4887b4897884493Refgit.kernel.org/stable/c/9884f745108f7d25b189bbcd6754e284fb29ab68Refgit.kernel.org/stable/c/992de06308d9a9584d59b96d294ac676f924e437Refgit.kernel.org/stable/c/e7d7bedd507bb732e600403b7a96f9fe48d0ca31Refgit.kernel.org/stable/c/efe1532a6e1a8e3c343d04fff510f0ed80328f9cRefgit.kernel.org/stable/c/6c1ea8bee75df8fe2184a50fcd0f70bf82986f42Refgit.kernel.org/stable/c/8d432592f30fcc34ef5a10aac4887b4897884493Refgit.kernel.org/stable/c/9884f745108f7d25b189bbcd6754e284fb29ab68Refgit.kernel.org/stable/c/992de06308d9a9584d59b96d294ac676f924e437

How CyberStrike helps

Frequently asked questions

What is CVE-2021-47010?

CVE-2021-47010 is a high-severity vulnerability. It was published on February 28, 2024 and has a CVSS 3.1 base score of 7.8 (HIGH).

How severe is CVE-2021-47010?

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-2021-47010?

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-2021-47010?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-47010 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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