PT-2021-8269 · Linux+1 · Linux Kernel+1

Jonathon Reinhart · Published 2021-05-01 · Updated 2025-03-19 · CVE-2021-47010

Positive Technologies (AI Summary)

CVSS v3.1

7.8

High

Base vector

AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description The issue is related to the tcp set default congestion control() function in the Linux kernel, which has an unintended side-effect of changing the global net.ipv4.tcp allowed congestion control sysctl, despite being read-only. This is due to the function setting ca->flags |= TCP CONG NON RESTRICTED, which is not namespaced. The restriction could be removed if tcp allowed congestion control were namespace-ified in the future. The bug was uncovered with the help of a tool available at https://github.com/JonathonReinhart/linux-netns-sysctl-verify.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Resource Exhaustion

Weakness Enumeration

CWE-400

Related Identifiers

BDU:2025-00809

CVE-2021-47010

Affected Products

Astra Linux

Linux Kernel

References · 22

• https://git.kernel.org/stable/c/8d432592f30fcc34ef5a10aac4887b4897884493 · Patch
• https://osv.dev/vulnerability/UBUNTU-CVE-2021-47010 · Vendor Advisory
• https://git.kernel.org/stable/c/efe1532a6e1a8e3c343d04fff510f0ed80328f9c · Patch
• https://bdu.fstec.ru/vul/2025-00809 · Security Note
• https://git.kernel.org/stable/c/6c1ea8bee75df8fe2184a50fcd0f70bf82986f42 · Patch
• https://git.kernel.org/stable/c/992de06308d9a9584d59b96d294ac676f924e437 · Patch
• https://git.kernel.org/stable/c/e7d7bedd507bb732e600403b7a96f9fe48d0ca31 · Patch
• https://security-tracker.debian.org/tracker/CVE-2021-47010 · Vendor Advisory
• https://cve.org/CVERecord?id=CVE-2021-47010 · Security Note
• https://git.kernel.org/stable/c/9884f745108f7d25b189bbcd6754e284fb29ab68 · Patch
• https://osv.dev/vulnerability/DEBIAN-CVE-2021-47010 · Vendor Advisory
• https://ubuntu.com/security/CVE-2021-47010 · Vendor Advisory
• https://wiki.astralinux.ru/astra-linux-se81-bulletin-20241206SE81 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2021-47010 · Security Note
• https://osv.dev/vulnerability/CVE-2021-47010 · Vendor Advisory